I am done

rl/Lib/site-packages/absl/flags/__init__.py

@@ -0,0 +1,225 @@
+# Copyright 2017 The Abseil Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""This package is used to define and parse command line flags.
+
+This package defines a *distributed* flag-definition policy: rather than
+an application having to define all flags in or near main(), each Python
+module defines flags that are useful to it.  When one Python module
+imports another, it gains access to the other's flags.  (This is
+implemented by having all modules share a common, global registry object
+containing all the flag information.)
+
+Flags are defined through the use of one of the DEFINE_xxx functions.
+The specific function used determines how the flag is parsed, checked,
+and optionally type-converted, when it's seen on the command line.
+"""
+
+import getopt
+import os
+import re
+import sys
+import types
+import warnings
+
+from absl.flags import _argument_parser
+from absl.flags import _defines
+from absl.flags import _exceptions
+from absl.flags import _flag
+from absl.flags import _flagvalues
+from absl.flags import _helpers
+from absl.flags import _validators
+
+__all__ = (
+    'DEFINE',
+    'DEFINE_flag',
+    'DEFINE_string',
+    'DEFINE_boolean',
+    'DEFINE_bool',
+    'DEFINE_float',
+    'DEFINE_integer',
+    'DEFINE_enum',
+    'DEFINE_enum_class',
+    'DEFINE_list',
+    'DEFINE_spaceseplist',
+    'DEFINE_multi',
+    'DEFINE_multi_string',
+    'DEFINE_multi_integer',
+    'DEFINE_multi_float',
+    'DEFINE_multi_enum',
+    'DEFINE_multi_enum_class',
+    'DEFINE_alias',
+    # Flag validators.
+    'register_validator',
+    'validator',
+    'register_multi_flags_validator',
+    'multi_flags_validator',
+    'mark_flag_as_required',
+    'mark_flags_as_required',
+    'mark_flags_as_mutual_exclusive',
+    'mark_bool_flags_as_mutual_exclusive',
+    # Flag modifiers.
+    'set_default',
+    'override_value',
+    # Key flag related functions.
+    'declare_key_flag',
+    'adopt_module_key_flags',
+    'disclaim_key_flags',
+    # Module exceptions.
+    'Error',
+    'CantOpenFlagFileError',
+    'DuplicateFlagError',
+    'IllegalFlagValueError',
+    'UnrecognizedFlagError',
+    'UnparsedFlagAccessError',
+    'ValidationError',
+    'FlagNameConflictsWithMethodError',
+    # Public classes.
+    'Flag',
+    'BooleanFlag',
+    'EnumFlag',
+    'EnumClassFlag',
+    'MultiFlag',
+    'MultiEnumClassFlag',
+    'FlagHolder',
+    'FlagValues',
+    'ArgumentParser',
+    'BooleanParser',
+    'EnumParser',
+    'EnumClassParser',
+    'ArgumentSerializer',
+    'FloatParser',
+    'IntegerParser',
+    'BaseListParser',
+    'ListParser',
+    'ListSerializer',
+    'EnumClassListSerializer',
+    'CsvListSerializer',
+    'WhitespaceSeparatedListParser',
+    'EnumClassSerializer',
+    # Helper functions.
+    'get_help_width',
+    'text_wrap',
+    'flag_dict_to_args',
+    'doc_to_help',
+    # The global FlagValues instance.
+    'FLAGS',
+)
+
+# Initialize the FLAGS_MODULE as early as possible.
+# It's only used by adopt_module_key_flags to take SPECIAL_FLAGS into account.
+_helpers.FLAGS_MODULE = sys.modules[__name__]
+
+# Add current module to disclaimed module ids.
+_helpers.disclaim_module_ids.add(id(sys.modules[__name__]))
+
+# DEFINE functions. They are explained in more details in the module doc string.
+# pylint: disable=invalid-name
+DEFINE = _defines.DEFINE
+DEFINE_flag = _defines.DEFINE_flag
+DEFINE_string = _defines.DEFINE_string
+DEFINE_boolean = _defines.DEFINE_boolean
+DEFINE_bool = DEFINE_boolean  # Match C++ API.
+DEFINE_float = _defines.DEFINE_float
+DEFINE_integer = _defines.DEFINE_integer
+DEFINE_enum = _defines.DEFINE_enum
+DEFINE_enum_class = _defines.DEFINE_enum_class
+DEFINE_list = _defines.DEFINE_list
+DEFINE_spaceseplist = _defines.DEFINE_spaceseplist
+DEFINE_multi = _defines.DEFINE_multi
+DEFINE_multi_string = _defines.DEFINE_multi_string
+DEFINE_multi_integer = _defines.DEFINE_multi_integer
+DEFINE_multi_float = _defines.DEFINE_multi_float
+DEFINE_multi_enum = _defines.DEFINE_multi_enum
+DEFINE_multi_enum_class = _defines.DEFINE_multi_enum_class
+DEFINE_alias = _defines.DEFINE_alias
+# pylint: enable=invalid-name
+
+# Flag validators.
+register_validator = _validators.register_validator
+validator = _validators.validator
+register_multi_flags_validator = _validators.register_multi_flags_validator
+multi_flags_validator = _validators.multi_flags_validator
+mark_flag_as_required = _validators.mark_flag_as_required
+mark_flags_as_required = _validators.mark_flags_as_required
+mark_flags_as_mutual_exclusive = _validators.mark_flags_as_mutual_exclusive
+mark_bool_flags_as_mutual_exclusive = _validators.mark_bool_flags_as_mutual_exclusive
+
+# Flag modifiers.
+set_default = _defines.set_default
+override_value = _defines.override_value
+
+# Key flag related functions.
+declare_key_flag = _defines.declare_key_flag
+adopt_module_key_flags = _defines.adopt_module_key_flags
+disclaim_key_flags = _defines.disclaim_key_flags
+
+# Module exceptions.
+# pylint: disable=invalid-name
+Error = _exceptions.Error
+CantOpenFlagFileError = _exceptions.CantOpenFlagFileError
+DuplicateFlagError = _exceptions.DuplicateFlagError
+IllegalFlagValueError = _exceptions.IllegalFlagValueError
+UnrecognizedFlagError = _exceptions.UnrecognizedFlagError
+UnparsedFlagAccessError = _exceptions.UnparsedFlagAccessError
+ValidationError = _exceptions.ValidationError
+FlagNameConflictsWithMethodError = _exceptions.FlagNameConflictsWithMethodError
+
+# Public classes.
+Flag = _flag.Flag
+BooleanFlag = _flag.BooleanFlag
+EnumFlag = _flag.EnumFlag
+EnumClassFlag = _flag.EnumClassFlag
+MultiFlag = _flag.MultiFlag
+MultiEnumClassFlag = _flag.MultiEnumClassFlag
+FlagHolder = _flagvalues.FlagHolder
+FlagValues = _flagvalues.FlagValues
+ArgumentParser = _argument_parser.ArgumentParser
+BooleanParser = _argument_parser.BooleanParser
+EnumParser = _argument_parser.EnumParser
+EnumClassParser = _argument_parser.EnumClassParser
+ArgumentSerializer = _argument_parser.ArgumentSerializer
+FloatParser = _argument_parser.FloatParser
+IntegerParser = _argument_parser.IntegerParser
+BaseListParser = _argument_parser.BaseListParser
+ListParser = _argument_parser.ListParser
+ListSerializer = _argument_parser.ListSerializer
+EnumClassListSerializer = _argument_parser.EnumClassListSerializer
+CsvListSerializer = _argument_parser.CsvListSerializer
+WhitespaceSeparatedListParser = _argument_parser.WhitespaceSeparatedListParser
+EnumClassSerializer = _argument_parser.EnumClassSerializer
+# pylint: enable=invalid-name
+
+# Helper functions.
+get_help_width = _helpers.get_help_width
+text_wrap = _helpers.text_wrap
+flag_dict_to_args = _helpers.flag_dict_to_args
+doc_to_help = _helpers.doc_to_help
+
+# Special flags.
+_helpers.SPECIAL_FLAGS = FlagValues()
+
+DEFINE_string(
+    'flagfile', '',
+    'Insert flag definitions from the given file into the command line.',
+    _helpers.SPECIAL_FLAGS)  # pytype: disable=wrong-arg-types
+
+DEFINE_string('undefok', '',
+              'comma-separated list of flag names that it is okay to specify '
+              'on the command line even if the program does not define a flag '
+              'with that name.  IMPORTANT: flags in this list that have '
+              'arguments MUST use the --flag=value format.',
+              _helpers.SPECIAL_FLAGS)  # pytype: disable=wrong-arg-types
+
+#: The global FlagValues instance.
+FLAGS = _flagvalues.FLAGS

rl/Lib/site-packages/absl/flags/_argument_parser.py

@@ -0,0 +1,638 @@
+# Copyright 2017 The Abseil Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Contains base classes used to parse and convert arguments.
+
+Do NOT import this module directly. Import the flags package and use the
+aliases defined at the package level instead.
+"""
+
+import collections
+import csv
+import enum
+import io
+import string
+from typing import Generic, List, Iterable, Optional, Sequence, Text, Type, TypeVar, Union
+from xml.dom import minidom
+
+from absl.flags import _helpers
+
+_T = TypeVar('_T')
+_ET = TypeVar('_ET', bound=enum.Enum)
+_N = TypeVar('_N', int, float)
+
+
+def _is_integer_type(instance):
+  """Returns True if instance is an integer, and not a bool."""
+  return (isinstance(instance, int) and
+          not isinstance(instance, bool))
+
+
+class _ArgumentParserCache(type):
+  """Metaclass used to cache and share argument parsers among flags."""
+
+  _instances = {}
+
+  def __call__(cls, *args, **kwargs):
+    """Returns an instance of the argument parser cls.
+
+    This method overrides behavior of the __new__ methods in
+    all subclasses of ArgumentParser (inclusive). If an instance
+    for cls with the same set of arguments exists, this instance is
+    returned, otherwise a new instance is created.
+
+    If any keyword arguments are defined, or the values in args
+    are not hashable, this method always returns a new instance of
+    cls.
+
+    Args:
+      *args: Positional initializer arguments.
+      **kwargs: Initializer keyword arguments.
+
+    Returns:
+      An instance of cls, shared or new.
+    """
+    if kwargs:
+      return type.__call__(cls, *args, **kwargs)
+    else:
+      instances = cls._instances
+      key = (cls,) + tuple(args)
+      try:
+        return instances[key]
+      except KeyError:
+        # No cache entry for key exists, create a new one.
+        return instances.setdefault(key, type.__call__(cls, *args))
+      except TypeError:
+        # An object in args cannot be hashed, always return
+        # a new instance.
+        return type.__call__(cls, *args)
+
+
+class ArgumentParser(Generic[_T], metaclass=_ArgumentParserCache):
+  """Base class used to parse and convert arguments.
+
+  The :meth:`parse` method checks to make sure that the string argument is a
+  legal value and convert it to a native type.  If the value cannot be
+  converted, it should throw a ``ValueError`` exception with a human
+  readable explanation of why the value is illegal.
+
+  Subclasses should also define a syntactic_help string which may be
+  presented to the user to describe the form of the legal values.
+
+  Argument parser classes must be stateless, since instances are cached
+  and shared between flags. Initializer arguments are allowed, but all
+  member variables must be derived from initializer arguments only.
+  """
+
+  syntactic_help: Text = ''
+
+  def parse(self, argument: Text) -> Optional[_T]:
+    """Parses the string argument and returns the native value.
+
+    By default it returns its argument unmodified.
+
+    Args:
+      argument: string argument passed in the commandline.
+
+    Raises:
+      ValueError: Raised when it fails to parse the argument.
+      TypeError: Raised when the argument has the wrong type.
+
+    Returns:
+      The parsed value in native type.
+    """
+    if not isinstance(argument, str):
+      raise TypeError('flag value must be a string, found "{}"'.format(
+          type(argument)))
+    return argument
+
+  def flag_type(self) -> Text:
+    """Returns a string representing the type of the flag."""
+    return 'string'
+
+  def _custom_xml_dom_elements(
+      self, doc: minidom.Document
+  ) -> List[minidom.Element]:
+    """Returns a list of minidom.Element to add additional flag information.
+
+    Args:
+      doc: minidom.Document, the DOM document it should create nodes from.
+    """
+    del doc  # Unused.
+    return []
+
+
+class ArgumentSerializer(Generic[_T]):
+  """Base class for generating string representations of a flag value."""
+
+  def serialize(self, value: _T) -> Text:
+    """Returns a serialized string of the value."""
+    return str(value)
+
+
+class NumericParser(ArgumentParser[_N]):
+  """Parser of numeric values.
+
+  Parsed value may be bounded to a given upper and lower bound.
+  """
+
+  lower_bound: Optional[_N]
+  upper_bound: Optional[_N]
+
+  def is_outside_bounds(self, val: _N) -> bool:
+    """Returns whether the value is outside the bounds or not."""
+    return ((self.lower_bound is not None and val < self.lower_bound) or
+            (self.upper_bound is not None and val > self.upper_bound))
+
+  def parse(self, argument: Text) -> _N:
+    """See base class."""
+    val = self.convert(argument)
+    if self.is_outside_bounds(val):
+      raise ValueError('%s is not %s' % (val, self.syntactic_help))
+    return val
+
+  def _custom_xml_dom_elements(
+      self, doc: minidom.Document
+  ) -> List[minidom.Element]:
+    elements = []
+    if self.lower_bound is not None:
+      elements.append(_helpers.create_xml_dom_element(
+          doc, 'lower_bound', self.lower_bound))
+    if self.upper_bound is not None:
+      elements.append(_helpers.create_xml_dom_element(
+          doc, 'upper_bound', self.upper_bound))
+    return elements
+
+  def convert(self, argument: Text) -> _N:
+    """Returns the correct numeric value of argument.
+
+    Subclass must implement this method, and raise TypeError if argument is not
+    string or has the right numeric type.
+
+    Args:
+      argument: string argument passed in the commandline, or the numeric type.
+
+    Raises:
+      TypeError: Raised when argument is not a string or the right numeric type.
+      ValueError: Raised when failed to convert argument to the numeric value.
+    """
+    raise NotImplementedError
+
+
+class FloatParser(NumericParser[float]):
+  """Parser of floating point values.
+
+  Parsed value may be bounded to a given upper and lower bound.
+  """
+  number_article = 'a'
+  number_name = 'number'
+  syntactic_help = ' '.join((number_article, number_name))
+
+  def __init__(
+      self,
+      lower_bound: Optional[float] = None,
+      upper_bound: Optional[float] = None,
+  ) -> None:
+    super(FloatParser, self).__init__()
+    self.lower_bound = lower_bound
+    self.upper_bound = upper_bound
+    sh = self.syntactic_help
+    if lower_bound is not None and upper_bound is not None:
+      sh = ('%s in the range [%s, %s]' % (sh, lower_bound, upper_bound))
+    elif lower_bound == 0:
+      sh = 'a non-negative %s' % self.number_name
+    elif upper_bound == 0:
+      sh = 'a non-positive %s' % self.number_name
+    elif upper_bound is not None:
+      sh = '%s <= %s' % (self.number_name, upper_bound)
+    elif lower_bound is not None:
+      sh = '%s >= %s' % (self.number_name, lower_bound)
+    self.syntactic_help = sh
+
+  def convert(self, argument: Union[int, float, str]) -> float:
+    """Returns the float value of argument."""
+    if (_is_integer_type(argument) or isinstance(argument, float) or
+        isinstance(argument, str)):
+      return float(argument)
+    else:
+      raise TypeError(
+          'Expect argument to be a string, int, or float, found {}'.format(
+              type(argument)))
+
+  def flag_type(self) -> Text:
+    """See base class."""
+    return 'float'
+
+
+class IntegerParser(NumericParser[int]):
+  """Parser of an integer value.
+
+  Parsed value may be bounded to a given upper and lower bound.
+  """
+  number_article = 'an'
+  number_name = 'integer'
+  syntactic_help = ' '.join((number_article, number_name))
+
+  def __init__(
+      self, lower_bound: Optional[int] = None, upper_bound: Optional[int] = None
+  ) -> None:
+    super(IntegerParser, self).__init__()
+    self.lower_bound = lower_bound
+    self.upper_bound = upper_bound
+    sh = self.syntactic_help
+    if lower_bound is not None and upper_bound is not None:
+      sh = ('%s in the range [%s, %s]' % (sh, lower_bound, upper_bound))
+    elif lower_bound == 1:
+      sh = 'a positive %s' % self.number_name
+    elif upper_bound == -1:
+      sh = 'a negative %s' % self.number_name
+    elif lower_bound == 0:
+      sh = 'a non-negative %s' % self.number_name
+    elif upper_bound == 0:
+      sh = 'a non-positive %s' % self.number_name
+    elif upper_bound is not None:
+      sh = '%s <= %s' % (self.number_name, upper_bound)
+    elif lower_bound is not None:
+      sh = '%s >= %s' % (self.number_name, lower_bound)
+    self.syntactic_help = sh
+
+  def convert(self, argument: Union[int, Text]) -> int:
+    """Returns the int value of argument."""
+    if _is_integer_type(argument):
+      return argument
+    elif isinstance(argument, str):
+      base = 10
+      if len(argument) > 2 and argument[0] == '0':
+        if argument[1] == 'o':
+          base = 8
+        elif argument[1] == 'x':
+          base = 16
+      return int(argument, base)
+    else:
+      raise TypeError('Expect argument to be a string or int, found {}'.format(
+          type(argument)))
+
+  def flag_type(self) -> Text:
+    """See base class."""
+    return 'int'
+
+
+class BooleanParser(ArgumentParser[bool]):
+  """Parser of boolean values."""
+
+  def parse(self, argument: Union[Text, int]) -> bool:
+    """See base class."""
+    if isinstance(argument, str):
+      if argument.lower() in ('true', 't', '1'):
+        return True
+      elif argument.lower() in ('false', 'f', '0'):
+        return False
+      else:
+        raise ValueError('Non-boolean argument to boolean flag', argument)
+    elif isinstance(argument, int):
+      # Only allow bool or integer 0, 1.
+      # Note that float 1.0 == True, 0.0 == False.
+      bool_value = bool(argument)
+      if argument == bool_value:
+        return bool_value
+      else:
+        raise ValueError('Non-boolean argument to boolean flag', argument)
+
+    raise TypeError('Non-boolean argument to boolean flag', argument)
+
+  def flag_type(self) -> Text:
+    """See base class."""
+    return 'bool'
+
+
+class EnumParser(ArgumentParser[Text]):
+  """Parser of a string enum value (a string value from a given set)."""
+
+  def __init__(
+      self, enum_values: Iterable[Text], case_sensitive: bool = True
+  ) -> None:
+    """Initializes EnumParser.
+
+    Args:
+      enum_values: [str], a non-empty list of string values in the enum.
+      case_sensitive: bool, whether or not the enum is to be case-sensitive.
+
+    Raises:
+      ValueError: When enum_values is empty.
+    """
+    if not enum_values:
+      raise ValueError(
+          'enum_values cannot be empty, found "{}"'.format(enum_values))
+    if isinstance(enum_values, str):
+      raise ValueError(
+          'enum_values cannot be a str, found "{}"'.format(enum_values)
+      )
+    super(EnumParser, self).__init__()
+    self.enum_values = list(enum_values)
+    self.case_sensitive = case_sensitive
+
+  def parse(self, argument: Text) -> Text:
+    """Determines validity of argument and returns the correct element of enum.
+
+    Args:
+      argument: str, the supplied flag value.
+
+    Returns:
+      The first matching element from enum_values.
+
+    Raises:
+      ValueError: Raised when argument didn't match anything in enum.
+    """
+    if self.case_sensitive:
+      if argument not in self.enum_values:
+        raise ValueError('value should be one of <%s>' %
+                         '|'.join(self.enum_values))
+      else:
+        return argument
+    else:
+      if argument.upper() not in [value.upper() for value in self.enum_values]:
+        raise ValueError('value should be one of <%s>' %
+                         '|'.join(self.enum_values))
+      else:
+        return [value for value in self.enum_values
+                if value.upper() == argument.upper()][0]
+
+  def flag_type(self) -> Text:
+    """See base class."""
+    return 'string enum'
+
+
+class EnumClassParser(ArgumentParser[_ET]):
+  """Parser of an Enum class member."""
+
+  def __init__(
+      self, enum_class: Type[_ET], case_sensitive: bool = True
+  ) -> None:
+    """Initializes EnumParser.
+
+    Args:
+      enum_class: class, the Enum class with all possible flag values.
+      case_sensitive: bool, whether or not the enum is to be case-sensitive. If
+        False, all member names must be unique when case is ignored.
+
+    Raises:
+      TypeError: When enum_class is not a subclass of Enum.
+      ValueError: When enum_class is empty.
+    """
+    if not issubclass(enum_class, enum.Enum):
+      raise TypeError('{} is not a subclass of Enum.'.format(enum_class))
+    if not enum_class.__members__:
+      raise ValueError('enum_class cannot be empty, but "{}" is empty.'
+                       .format(enum_class))
+    if not case_sensitive:
+      members = collections.Counter(
+          name.lower() for name in enum_class.__members__)
+      duplicate_keys = {
+          member for member, count in members.items() if count > 1
+      }
+      if duplicate_keys:
+        raise ValueError(
+            'Duplicate enum values for {} using case_sensitive=False'.format(
+                duplicate_keys))
+
+    super(EnumClassParser, self).__init__()
+    self.enum_class = enum_class
+    self._case_sensitive = case_sensitive
+    if case_sensitive:
+      self._member_names = tuple(enum_class.__members__)
+    else:
+      self._member_names = tuple(
+          name.lower() for name in enum_class.__members__)
+
+  @property
+  def member_names(self) -> Sequence[Text]:
+    """The accepted enum names, in lowercase if not case sensitive."""
+    return self._member_names
+
+  def parse(self, argument: Union[_ET, Text]) -> _ET:
+    """Determines validity of argument and returns the correct element of enum.
+
+    Args:
+      argument: str or Enum class member, the supplied flag value.
+
+    Returns:
+      The first matching Enum class member in Enum class.
+
+    Raises:
+      ValueError: Raised when argument didn't match anything in enum.
+    """
+    if isinstance(argument, self.enum_class):
+      return argument  # pytype: disable=bad-return-type
+    elif not isinstance(argument, str):
+      raise ValueError(
+          '{} is not an enum member or a name of a member in {}'.format(
+              argument, self.enum_class))
+    key = EnumParser(
+        self._member_names, case_sensitive=self._case_sensitive).parse(argument)
+    if self._case_sensitive:
+      return self.enum_class[key]
+    else:
+      # If EnumParser.parse() return a value, we're guaranteed to find it
+      # as a member of the class
+      return next(value for name, value in self.enum_class.__members__.items()
+                  if name.lower() == key.lower())
+
+  def flag_type(self) -> Text:
+    """See base class."""
+    return 'enum class'
+
+
+class ListSerializer(Generic[_T], ArgumentSerializer[List[_T]]):
+
+  def __init__(self, list_sep: Text) -> None:
+    self.list_sep = list_sep
+
+  def serialize(self, value: List[_T]) -> Text:
+    """See base class."""
+    return self.list_sep.join([str(x) for x in value])
+
+
+class EnumClassListSerializer(ListSerializer[_ET]):
+  """A serializer for :class:`MultiEnumClass` flags.
+
+  This serializer simply joins the output of `EnumClassSerializer` using a
+  provided separator.
+  """
+
+  def __init__(self, list_sep: Text, **kwargs) -> None:
+    """Initializes EnumClassListSerializer.
+
+    Args:
+      list_sep: String to be used as a separator when serializing
+      **kwargs: Keyword arguments to the `EnumClassSerializer` used to serialize
+        individual values.
+    """
+    super(EnumClassListSerializer, self).__init__(list_sep)
+    self._element_serializer = EnumClassSerializer(**kwargs)
+
+  def serialize(self, value: Union[_ET, List[_ET]]) -> Text:
+    """See base class."""
+    if isinstance(value, list):
+      return self.list_sep.join(
+          self._element_serializer.serialize(x) for x in value)
+    else:
+      return self._element_serializer.serialize(value)
+
+
+class CsvListSerializer(ListSerializer[Text]):
+
+  def serialize(self, value: List[Text]) -> Text:
+    """Serializes a list as a CSV string or unicode."""
+    output = io.StringIO()
+    writer = csv.writer(output, delimiter=self.list_sep)
+    writer.writerow([str(x) for x in value])
+    serialized_value = output.getvalue().strip()
+
+    # We need the returned value to be pure ascii or Unicodes so that
+    # when the xml help is generated they are usefully encodable.
+    return str(serialized_value)
+
+
+class EnumClassSerializer(ArgumentSerializer[_ET]):
+  """Class for generating string representations of an enum class flag value."""
+
+  def __init__(self, lowercase: bool) -> None:
+    """Initializes EnumClassSerializer.
+
+    Args:
+      lowercase: If True, enum member names are lowercased during serialization.
+    """
+    self._lowercase = lowercase
+
+  def serialize(self, value: _ET) -> Text:
+    """Returns a serialized string of the Enum class value."""
+    as_string = str(value.name)
+    return as_string.lower() if self._lowercase else as_string
+
+
+class BaseListParser(ArgumentParser):
+  """Base class for a parser of lists of strings.
+
+  To extend, inherit from this class; from the subclass ``__init__``, call::
+
+      super().__init__(token, name)
+
+  where token is a character used to tokenize, and name is a description
+  of the separator.
+  """
+
+  def __init__(
+      self, token: Optional[Text] = None, name: Optional[Text] = None
+  ) -> None:
+    assert name
+    super(BaseListParser, self).__init__()
+    self._token = token
+    self._name = name
+    self.syntactic_help = 'a %s separated list' % self._name
+
+  def parse(self, argument: Text) -> List[Text]:
+    """See base class."""
+    if isinstance(argument, list):
+      return argument
+    elif not argument:
+      return []
+    else:
+      return [s.strip() for s in argument.split(self._token)]
+
+  def flag_type(self) -> Text:
+    """See base class."""
+    return '%s separated list of strings' % self._name
+
+
+class ListParser(BaseListParser):
+  """Parser for a comma-separated list of strings."""
+
+  def __init__(self) -> None:
+    super(ListParser, self).__init__(',', 'comma')
+
+  def parse(self, argument: Union[Text, List[Text]]) -> List[Text]:
+    """Parses argument as comma-separated list of strings."""
+    if isinstance(argument, list):
+      return argument
+    elif not argument:
+      return []
+    else:
+      try:
+        return [s.strip() for s in list(csv.reader([argument], strict=True))[0]]
+      except csv.Error as e:
+        # Provide a helpful report for case like
+        #   --listflag="$(printf 'hello,\nworld')"
+        # IOW, list flag values containing naked newlines.  This error
+        # was previously "reported" by allowing csv.Error to
+        # propagate.
+        raise ValueError('Unable to parse the value %r as a %s: %s'
+                         % (argument, self.flag_type(), e))
+
+  def _custom_xml_dom_elements(
+      self, doc: minidom.Document
+  ) -> List[minidom.Element]:
+    elements = super(ListParser, self)._custom_xml_dom_elements(doc)
+    elements.append(_helpers.create_xml_dom_element(
+        doc, 'list_separator', repr(',')))
+    return elements
+
+
+class WhitespaceSeparatedListParser(BaseListParser):
+  """Parser for a whitespace-separated list of strings."""
+
+  def __init__(self, comma_compat: bool = False) -> None:
+    """Initializer.
+
+    Args:
+      comma_compat: bool, whether to support comma as an additional separator.
+          If False then only whitespace is supported.  This is intended only for
+          backwards compatibility with flags that used to be comma-separated.
+    """
+    self._comma_compat = comma_compat
+    name = 'whitespace or comma' if self._comma_compat else 'whitespace'
+    super(WhitespaceSeparatedListParser, self).__init__(None, name)
+
+  def parse(self, argument: Union[Text, List[Text]]) -> List[Text]:
+    """Parses argument as whitespace-separated list of strings.
+
+    It also parses argument as comma-separated list of strings if requested.
+
+    Args:
+      argument: string argument passed in the commandline.
+
+    Returns:
+      [str], the parsed flag value.
+    """
+    if isinstance(argument, list):
+      return argument
+    elif not argument:
+      return []
+    else:
+      if self._comma_compat:
+        argument = argument.replace(',', ' ')
+      return argument.split()
+
+  def _custom_xml_dom_elements(
+      self, doc: minidom.Document
+  ) -> List[minidom.Element]:
+    elements = super(WhitespaceSeparatedListParser, self
+                    )._custom_xml_dom_elements(doc)
+    separators = list(string.whitespace)
+    if self._comma_compat:
+      separators.append(',')
+    separators.sort()
+    for sep_char in separators:
+      elements.append(_helpers.create_xml_dom_element(
+          doc, 'list_separator', repr(sep_char)))
+    return elements

rl/Lib/site-packages/absl/flags/_exceptions.py

@@ -0,0 +1,108 @@
+# Copyright 2017 The Abseil Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Exception classes in ABSL flags library.
+
+Do NOT import this module directly. Import the flags package and use the
+aliases defined at the package level instead.
+"""
+
+import sys
+
+from absl.flags import _helpers
+
+
+_helpers.disclaim_module_ids.add(id(sys.modules[__name__]))
+
+
+class Error(Exception):
+  """The base class for all flags errors."""
+
+
+class CantOpenFlagFileError(Error):
+  """Raised when flagfile fails to open.
+
+  E.g. the file doesn't exist, or has wrong permissions.
+  """
+
+
+class DuplicateFlagError(Error):
+  """Raised if there is a flag naming conflict."""
+
+  @classmethod
+  def from_flag(cls, flagname, flag_values, other_flag_values=None):
+    """Creates a DuplicateFlagError by providing flag name and values.
+
+    Args:
+      flagname: str, the name of the flag being redefined.
+      flag_values: :class:`FlagValues`, the FlagValues instance containing the
+        first definition of flagname.
+      other_flag_values: :class:`FlagValues`, if it is not None, it should be
+        the FlagValues object where the second definition of flagname occurs.
+        If it is None, we assume that we're being called when attempting to
+        create the flag a second time, and we use the module calling this one
+        as the source of the second definition.
+
+    Returns:
+      An instance of DuplicateFlagError.
+    """
+    first_module = flag_values.find_module_defining_flag(
+        flagname, default='<unknown>')
+    if other_flag_values is None:
+      second_module = _helpers.get_calling_module()
+    else:
+      second_module = other_flag_values.find_module_defining_flag(
+          flagname, default='<unknown>')
+    flag_summary = flag_values[flagname].help
+    msg = ("The flag '%s' is defined twice. First from %s, Second from %s.  "
+           "Description from first occurrence: %s") % (
+               flagname, first_module, second_module, flag_summary)
+    return cls(msg)
+
+
+class IllegalFlagValueError(Error):
+  """Raised when the flag command line argument is illegal."""
+
+
+class UnrecognizedFlagError(Error):
+  """Raised when a flag is unrecognized.
+
+  Attributes:
+    flagname: str, the name of the unrecognized flag.
+    flagvalue: The value of the flag, empty if the flag is not defined.
+  """
+
+  def __init__(self, flagname, flagvalue='', suggestions=None):
+    self.flagname = flagname
+    self.flagvalue = flagvalue
+    if suggestions:
+      # Space before the question mark is intentional to not include it in the
+      # selection when copy-pasting the suggestion from (some) terminals.
+      tip = '. Did you mean: %s ?' % ', '.join(suggestions)
+    else:
+      tip = ''
+    super(UnrecognizedFlagError, self).__init__(
+        'Unknown command line flag \'%s\'%s' % (flagname, tip))
+
+
+class UnparsedFlagAccessError(Error):
+  """Raised when accessing the flag value from unparsed :class:`FlagValues`."""
+
+
+class ValidationError(Error):
+  """Raised when flag validator constraint is not satisfied."""
+
+
+class FlagNameConflictsWithMethodError(Error):
+  """Raised when a flag name conflicts with :class:`FlagValues` methods."""

rl/Lib/site-packages/absl/flags/_flag.py

@@ -0,0 +1,556 @@
+# Copyright 2017 The Abseil Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Contains Flag class - information about single command-line flag.
+
+Do NOT import this module directly. Import the flags package and use the
+aliases defined at the package level instead.
+"""
+
+from collections import abc
+import copy
+import enum
+import functools
+from typing import Any, Dict, Generic, Iterable, List, Optional, Text, Type, TypeVar, Union
+from xml.dom import minidom
+
+from absl.flags import _argument_parser
+from absl.flags import _exceptions
+from absl.flags import _helpers
+
+_T = TypeVar('_T')
+_ET = TypeVar('_ET', bound=enum.Enum)
+
+
+@functools.total_ordering
+class Flag(Generic[_T]):
+  """Information about a command-line flag.
+
+  Attributes:
+    name: the name for this flag
+    default: the default value for this flag
+    default_unparsed: the unparsed default value for this flag.
+    default_as_str: default value as repr'd string, e.g., "'true'"
+      (or None)
+    value: the most recent parsed value of this flag set by :meth:`parse`
+    help: a help string or None if no help is available
+    short_name: the single letter alias for this flag (or None)
+    boolean: if 'true', this flag does not accept arguments
+    present: true if this flag was parsed from command line flags
+    parser: an :class:`~absl.flags.ArgumentParser` object
+    serializer: an ArgumentSerializer object
+    allow_override: the flag may be redefined without raising an error,
+      and newly defined flag overrides the old one.
+    allow_override_cpp: use the flag from C++ if available the flag
+      definition is replaced by the C++ flag after init
+    allow_hide_cpp: use the Python flag despite having a C++ flag with
+      the same name (ignore the C++ flag)
+    using_default_value: the flag value has not been set by user
+    allow_overwrite: the flag may be parsed more than once without
+      raising an error, the last set value will be used
+    allow_using_method_names: whether this flag can be defined even if
+      it has a name that conflicts with a FlagValues method.
+    validators: list of the flag validators.
+
+  The only public method of a ``Flag`` object is :meth:`parse`, but it is
+  typically only called by a :class:`~absl.flags.FlagValues` object.  The
+  :meth:`parse` method is a thin wrapper around the
+  :meth:`ArgumentParser.parse()<absl.flags.ArgumentParser.parse>` method.  The
+  parsed value is saved in ``.value``, and the ``.present`` attribute is
+  updated.  If this flag was already present, an Error is raised.
+
+  :meth:`parse` is also called during ``__init__`` to parse the default value
+  and initialize the ``.value`` attribute.  This enables other python modules to
+  safely use flags even if the ``__main__`` module neglects to parse the
+  command line arguments.  The ``.present`` attribute is cleared after
+  ``__init__`` parsing.  If the default value is set to ``None``, then the
+  ``__init__`` parsing step is skipped and the ``.value`` attribute is
+  initialized to None.
+
+  Note: The default value is also presented to the user in the help
+  string, so it is important that it be a legal value for this flag.
+  """
+
+  # NOTE: pytype doesn't find defaults without this.
+  default: Optional[_T]
+  default_as_str: Optional[Text]
+  default_unparsed: Union[Optional[_T], Text]
+
+  def __init__(
+      self,
+      parser: _argument_parser.ArgumentParser[_T],
+      serializer: Optional[_argument_parser.ArgumentSerializer[_T]],
+      name: Text,
+      default: Union[Optional[_T], Text],
+      help_string: Optional[Text],
+      short_name: Optional[Text] = None,
+      boolean: bool = False,
+      allow_override: bool = False,
+      allow_override_cpp: bool = False,
+      allow_hide_cpp: bool = False,
+      allow_overwrite: bool = True,
+      allow_using_method_names: bool = False,
+  ) -> None:
+    self.name = name
+
+    if not help_string:
+      help_string = '(no help available)'
+
+    self.help = help_string
+    self.short_name = short_name
+    self.boolean = boolean
+    self.present = 0
+    self.parser = parser
+    self.serializer = serializer
+    self.allow_override = allow_override
+    self.allow_override_cpp = allow_override_cpp
+    self.allow_hide_cpp = allow_hide_cpp
+    self.allow_overwrite = allow_overwrite
+    self.allow_using_method_names = allow_using_method_names
+
+    self.using_default_value = True
+    self._value = None
+    self.validators = []
+    if self.allow_hide_cpp and self.allow_override_cpp:
+      raise _exceptions.Error(
+          "Can't have both allow_hide_cpp (means use Python flag) and "
+          'allow_override_cpp (means use C++ flag after InitGoogle)')
+
+    self._set_default(default)
+
+  @property
+  def value(self) -> Optional[_T]:
+    return self._value
+
+  @value.setter
+  def value(self, value: Optional[_T]):
+    self._value = value
+
+  def __hash__(self):
+    return hash(id(self))
+
+  def __eq__(self, other):
+    return self is other
+
+  def __lt__(self, other):
+    if isinstance(other, Flag):
+      return id(self) < id(other)
+    return NotImplemented
+
+  def __bool__(self):
+    raise TypeError('A Flag instance would always be True. '
+                    'Did you mean to test the `.value` attribute?')
+
+  def __getstate__(self):
+    raise TypeError("can't pickle Flag objects")
+
+  def __copy__(self):
+    raise TypeError('%s does not support shallow copies. '
+                    'Use copy.deepcopy instead.' % type(self).__name__)
+
+  def __deepcopy__(self, memo: Dict[int, Any]) -> 'Flag[_T]':
+    result = object.__new__(type(self))
+    result.__dict__ = copy.deepcopy(self.__dict__, memo)
+    return result
+
+  def _get_parsed_value_as_string(self, value: Optional[_T]) -> Optional[Text]:
+    """Returns parsed flag value as string."""
+    if value is None:
+      return None
+    if self.serializer:
+      return repr(self.serializer.serialize(value))
+    if self.boolean:
+      if value:
+        return repr('true')
+      else:
+        return repr('false')
+    return repr(str(value))
+
+  def parse(self, argument: Union[Text, Optional[_T]]) -> None:
+    """Parses string and sets flag value.
+
+    Args:
+      argument: str or the correct flag value type, argument to be parsed.
+    """
+    if self.present and not self.allow_overwrite:
+      raise _exceptions.IllegalFlagValueError(
+          'flag --%s=%s: already defined as %s' % (
+              self.name, argument, self.value))
+    self.value = self._parse(argument)
+    self.present += 1
+
+  def _parse(self, argument: Union[Text, _T]) -> Optional[_T]:
+    """Internal parse function.
+
+    It returns the parsed value, and does not modify class states.
+
+    Args:
+      argument: str or the correct flag value type, argument to be parsed.
+
+    Returns:
+      The parsed value.
+    """
+    try:
+      return self.parser.parse(argument)
+    except (TypeError, ValueError) as e:  # Recast as IllegalFlagValueError.
+      raise _exceptions.IllegalFlagValueError(
+          'flag --%s=%s: %s' % (self.name, argument, e))
+
+  def unparse(self) -> None:
+    self.value = self.default
+    self.using_default_value = True
+    self.present = 0
+
+  def serialize(self) -> Text:
+    """Serializes the flag."""
+    return self._serialize(self.value)
+
+  def _serialize(self, value: Optional[_T]) -> Text:
+    """Internal serialize function."""
+    if value is None:
+      return ''
+    if self.boolean:
+      if value:
+        return '--%s' % self.name
+      else:
+        return '--no%s' % self.name
+    else:
+      if not self.serializer:
+        raise _exceptions.Error(
+            'Serializer not present for flag %s' % self.name)
+      return '--%s=%s' % (self.name, self.serializer.serialize(value))
+
+  def _set_default(self, value: Union[Optional[_T], Text]) -> None:
+    """Changes the default value (and current value too) for this Flag."""
+    self.default_unparsed = value
+    if value is None:
+      self.default = None
+    else:
+      self.default = self._parse_from_default(value)
+    self.default_as_str = self._get_parsed_value_as_string(self.default)
+    if self.using_default_value:
+      self.value = self.default
+
+  # This is split out so that aliases can skip regular parsing of the default
+  # value.
+  def _parse_from_default(self, value: Union[Text, _T]) -> Optional[_T]:
+    return self._parse(value)
+
+  def flag_type(self) -> Text:
+    """Returns a str that describes the type of the flag.
+
+    NOTE: we use strings, and not the types.*Type constants because
+    our flags can have more exotic types, e.g., 'comma separated list
+    of strings', 'whitespace separated list of strings', etc.
+    """
+    return self.parser.flag_type()
+
+  def _create_xml_dom_element(
+      self, doc: minidom.Document, module_name: str, is_key: bool = False
+  ) -> minidom.Element:
+    """Returns an XML element that contains this flag's information.
+
+    This is information that is relevant to all flags (e.g., name,
+    meaning, etc.).  If you defined a flag that has some other pieces of
+    info, then please override _ExtraXMLInfo.
+
+    Please do NOT override this method.
+
+    Args:
+      doc: minidom.Document, the DOM document it should create nodes from.
+      module_name: str,, the name of the module that defines this flag.
+      is_key: boolean, True iff this flag is key for main module.
+
+    Returns:
+      A minidom.Element instance.
+    """
+    element = doc.createElement('flag')
+    if is_key:
+      element.appendChild(_helpers.create_xml_dom_element(doc, 'key', 'yes'))
+    element.appendChild(_helpers.create_xml_dom_element(
+        doc, 'file', module_name))
+    # Adds flag features that are relevant for all flags.
+    element.appendChild(_helpers.create_xml_dom_element(doc, 'name', self.name))
+    if self.short_name:
+      element.appendChild(_helpers.create_xml_dom_element(
+          doc, 'short_name', self.short_name))
+    if self.help:
+      element.appendChild(_helpers.create_xml_dom_element(
+          doc, 'meaning', self.help))
+    # The default flag value can either be represented as a string like on the
+    # command line, or as a Python object.  We serialize this value in the
+    # latter case in order to remain consistent.
+    if self.serializer and not isinstance(self.default, str):
+      if self.default is not None:
+        default_serialized = self.serializer.serialize(self.default)
+      else:
+        default_serialized = ''
+    else:
+      default_serialized = self.default
+    element.appendChild(_helpers.create_xml_dom_element(
+        doc, 'default', default_serialized))
+    value_serialized = self._serialize_value_for_xml(self.value)
+    element.appendChild(_helpers.create_xml_dom_element(
+        doc, 'current', value_serialized))
+    element.appendChild(_helpers.create_xml_dom_element(
+        doc, 'type', self.flag_type()))
+    # Adds extra flag features this flag may have.
+    for e in self._extra_xml_dom_elements(doc):
+      element.appendChild(e)
+    return element
+
+  def _serialize_value_for_xml(self, value: Optional[_T]) -> Any:
+    """Returns the serialized value, for use in an XML help text."""
+    return value
+
+  def _extra_xml_dom_elements(
+      self, doc: minidom.Document
+  ) -> List[minidom.Element]:
+    """Returns extra info about this flag in XML.
+
+    "Extra" means "not already included by _create_xml_dom_element above."
+
+    Args:
+      doc: minidom.Document, the DOM document it should create nodes from.
+
+    Returns:
+      A list of minidom.Element.
+    """
+    # Usually, the parser knows the extra details about the flag, so
+    # we just forward the call to it.
+    return self.parser._custom_xml_dom_elements(doc)  # pylint: disable=protected-access
+
+
+class BooleanFlag(Flag[bool]):
+  """Basic boolean flag.
+
+  Boolean flags do not take any arguments, and their value is either
+  ``True`` (1) or ``False`` (0).  The false value is specified on the command
+  line by prepending the word ``'no'`` to either the long or the short flag
+  name.
+
+  For example, if a Boolean flag was created whose long name was
+  ``'update'`` and whose short name was ``'x'``, then this flag could be
+  explicitly unset through either ``--noupdate`` or ``--nox``.
+  """
+
+  def __init__(
+      self,
+      name: Text,
+      default: Union[Optional[bool], Text],
+      help: Optional[Text],  # pylint: disable=redefined-builtin
+      short_name: Optional[Text] = None,
+      **args
+  ) -> None:
+    p = _argument_parser.BooleanParser()
+    super(BooleanFlag, self).__init__(
+        p, None, name, default, help, short_name, True, **args
+    )
+
+
+class EnumFlag(Flag[Text]):
+  """Basic enum flag; its value can be any string from list of enum_values."""
+
+  def __init__(
+      self,
+      name: Text,
+      default: Optional[Text],
+      help: Optional[Text],  # pylint: disable=redefined-builtin
+      enum_values: Iterable[Text],
+      short_name: Optional[Text] = None,
+      case_sensitive: bool = True,
+      **args
+  ):
+    p = _argument_parser.EnumParser(enum_values, case_sensitive)
+    g = _argument_parser.ArgumentSerializer()
+    super(EnumFlag, self).__init__(
+        p, g, name, default, help, short_name, **args)
+    # NOTE: parser should be typed EnumParser but the constructor
+    # restricts the available interface to ArgumentParser[str].
+    self.parser = p
+    self.help = '<%s>: %s' % ('|'.join(p.enum_values), self.help)
+
+  def _extra_xml_dom_elements(
+      self, doc: minidom.Document
+  ) -> List[minidom.Element]:
+    elements = []
+    for enum_value in self.parser.enum_values:
+      elements.append(_helpers.create_xml_dom_element(
+          doc, 'enum_value', enum_value))
+    return elements
+
+
+class EnumClassFlag(Flag[_ET]):
+  """Basic enum flag; its value is an enum class's member."""
+
+  def __init__(
+      self,
+      name: Text,
+      default: Union[Optional[_ET], Text],
+      help: Optional[Text],  # pylint: disable=redefined-builtin
+      enum_class: Type[_ET],
+      short_name: Optional[Text] = None,
+      case_sensitive: bool = False,
+      **args
+  ):
+    p = _argument_parser.EnumClassParser(
+        enum_class, case_sensitive=case_sensitive)
+    g = _argument_parser.EnumClassSerializer(lowercase=not case_sensitive)
+    super(EnumClassFlag, self).__init__(
+        p, g, name, default, help, short_name, **args)
+    # NOTE: parser should be typed EnumClassParser[_ET] but the constructor
+    # restricts the available interface to ArgumentParser[_ET].
+    self.parser = p
+    self.help = '<%s>: %s' % ('|'.join(p.member_names), self.help)
+
+  def _extra_xml_dom_elements(
+      self, doc: minidom.Document
+  ) -> List[minidom.Element]:
+    elements = []
+    for enum_value in self.parser.enum_class.__members__.keys():
+      elements.append(_helpers.create_xml_dom_element(
+          doc, 'enum_value', enum_value))
+    return elements
+
+
+class MultiFlag(Generic[_T], Flag[List[_T]]):
+  """A flag that can appear multiple time on the command-line.
+
+  The value of such a flag is a list that contains the individual values
+  from all the appearances of that flag on the command-line.
+
+  See the __doc__ for Flag for most behavior of this class.  Only
+  differences in behavior are described here:
+
+    * The default value may be either a single value or an iterable of values.
+      A single value is transformed into a single-item list of that value.
+
+    * The value of the flag is always a list, even if the option was
+      only supplied once, and even if the default value is a single
+      value
+  """
+
+  def __init__(self, *args, **kwargs):
+    super(MultiFlag, self).__init__(*args, **kwargs)
+    self.help += ';\n    repeat this option to specify a list of values'
+
+  def parse(self, arguments: Union[Text, _T, Iterable[_T]]):  # pylint: disable=arguments-renamed
+    """Parses one or more arguments with the installed parser.
+
+    Args:
+      arguments: a single argument or a list of arguments (typically a
+        list of default values); a single argument is converted
+        internally into a list containing one item.
+    """
+    new_values = self._parse(arguments)
+    if self.present:
+      self.value.extend(new_values)
+    else:
+      self.value = new_values
+    self.present += len(new_values)
+
+  def _parse(self, arguments: Union[Text, Optional[Iterable[_T]]]) -> List[_T]:  # pylint: disable=arguments-renamed
+    if (isinstance(arguments, abc.Iterable) and
+        not isinstance(arguments, str)):
+      arguments = list(arguments)
+
+    if not isinstance(arguments, list):
+      # Default value may be a list of values.  Most other arguments
+      # will not be, so convert them into a single-item list to make
+      # processing simpler below.
+      arguments = [arguments]
+
+    return [super(MultiFlag, self)._parse(item) for item in arguments]
+
+  def _serialize(self, value: Optional[List[_T]]) -> Text:
+    """See base class."""
+    if not self.serializer:
+      raise _exceptions.Error(
+          'Serializer not present for flag %s' % self.name)
+    if value is None:
+      return ''
+
+    serialized_items = [
+        super(MultiFlag, self)._serialize(value_item) for value_item in value
+    ]
+
+    return '\n'.join(serialized_items)
+
+  def flag_type(self):
+    """See base class."""
+    return 'multi ' + self.parser.flag_type()
+
+  def _extra_xml_dom_elements(
+      self, doc: minidom.Document
+  ) -> List[minidom.Element]:
+    elements = []
+    if hasattr(self.parser, 'enum_values'):
+      for enum_value in self.parser.enum_values:  # pytype: disable=attribute-error
+        elements.append(_helpers.create_xml_dom_element(
+            doc, 'enum_value', enum_value))
+    return elements
+
+
+class MultiEnumClassFlag(MultiFlag[_ET]):  # pytype: disable=not-indexable
+  """A multi_enum_class flag.
+
+  See the __doc__ for MultiFlag for most behaviors of this class.  In addition,
+  this class knows how to handle enum.Enum instances as values for this flag
+  type.
+  """
+
+  def __init__(
+      self,
+      name: str,
+      default: Union[None, Iterable[_ET], _ET, Iterable[Text], Text],
+      help_string: str,
+      enum_class: Type[_ET],
+      case_sensitive: bool = False,
+      **args
+  ):
+    p = _argument_parser.EnumClassParser(
+        enum_class, case_sensitive=case_sensitive)
+    g = _argument_parser.EnumClassListSerializer(
+        list_sep=',', lowercase=not case_sensitive)
+    super(MultiEnumClassFlag, self).__init__(
+        p, g, name, default, help_string, **args)
+    # NOTE: parser should be typed EnumClassParser[_ET] but the constructor
+    # restricts the available interface to ArgumentParser[str].
+    self.parser = p
+    # NOTE: serializer should be non-Optional but this isn't inferred.
+    self.serializer = g
+    self.help = (
+        '<%s>: %s;\n    repeat this option to specify a list of values' %
+        ('|'.join(p.member_names), help_string or '(no help available)'))
+
+  def _extra_xml_dom_elements(
+      self, doc: minidom.Document
+  ) -> List[minidom.Element]:
+    elements = []
+    for enum_value in self.parser.enum_class.__members__.keys():  # pytype: disable=attribute-error
+      elements.append(_helpers.create_xml_dom_element(
+          doc, 'enum_value', enum_value))
+    return elements
+
+  def _serialize_value_for_xml(self, value):
+    """See base class."""
+    if value is not None:
+      if not self.serializer:
+        raise _exceptions.Error(
+            'Serializer not present for flag %s' % self.name
+        )
+      value_serialized = self.serializer.serialize(value)
+    else:
+      value_serialized = ''
+    return value_serialized

rl/Lib/site-packages/absl/flags/_helpers.py

@@ -0,0 +1,421 @@
+# Copyright 2017 The Abseil Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Internal helper functions for Abseil Python flags library."""
+
+import os
+import re
+import struct
+import sys
+import textwrap
+import types
+from typing import Any, Dict, Iterable, List, NamedTuple, Optional, Sequence, Set
+from xml.dom import minidom
+# pylint: disable=g-import-not-at-top
+try:
+  import fcntl
+except ImportError:
+  fcntl = None
+try:
+  # Importing termios will fail on non-unix platforms.
+  import termios
+except ImportError:
+  termios = None
+# pylint: enable=g-import-not-at-top
+
+
+_DEFAULT_HELP_WIDTH = 80  # Default width of help output.
+# Minimal "sane" width of help output. We assume that any value below 40 is
+# unreasonable.
+_MIN_HELP_WIDTH = 40
+
+# Define the allowed error rate in an input string to get suggestions.
+#
+# We lean towards a high threshold because we tend to be matching a phrase,
+# and the simple algorithm used here is geared towards correcting word
+# spellings.
+#
+# For manual testing, consider "<command> --list" which produced a large number
+# of spurious suggestions when we used "least_errors > 0.5" instead of
+# "least_erros >= 0.5".
+_SUGGESTION_ERROR_RATE_THRESHOLD = 0.50
+
+# Characters that cannot appear or are highly discouraged in an XML 1.0
+# document. (See http://www.w3.org/TR/REC-xml/#charsets or
+# https://en.wikipedia.org/wiki/Valid_characters_in_XML#XML_1.0)
+_ILLEGAL_XML_CHARS_REGEX = re.compile(
+    u'[\x00-\x08\x0b\x0c\x0e-\x1f\x7f-\x84\x86-\x9f\ud800-\udfff\ufffe\uffff]')
+
+# This is a set of module ids for the modules that disclaim key flags.
+# This module is explicitly added to this set so that we never consider it to
+# define key flag.
+disclaim_module_ids: Set[int] = set([id(sys.modules[__name__])])
+
+
+# Define special flags here so that help may be generated for them.
+# NOTE: Please do NOT use SPECIAL_FLAGS from outside flags module.
+# Initialized inside flagvalues.py.
+# NOTE: This cannot be annotated as its actual FlagValues type since this would
+# create a circular dependency.
+SPECIAL_FLAGS: Any = None
+
+
+# This points to the flags module, initialized in flags/__init__.py.
+# This should only be used in adopt_module_key_flags to take SPECIAL_FLAGS into
+# account.
+FLAGS_MODULE: types.ModuleType = None
+
+
+class _ModuleObjectAndName(NamedTuple):
+  """Module object and name.
+
+  Fields:
+  - module: object, module object.
+  - module_name: str, module name.
+  """
+  module: types.ModuleType
+  module_name: str
+
+
+def get_module_object_and_name(
+    globals_dict: Dict[str, Any]
+) -> _ModuleObjectAndName:
+  """Returns the module that defines a global environment, and its name.
+
+  Args:
+    globals_dict: A dictionary that should correspond to an environment
+      providing the values of the globals.
+
+  Returns:
+    _ModuleObjectAndName - pair of module object & module name.
+    Returns (None, None) if the module could not be identified.
+  """
+  name = globals_dict.get('__name__', None)
+  module = sys.modules.get(name, None)
+  # Pick a more informative name for the main module.
+  return _ModuleObjectAndName(module,
+                              (sys.argv[0] if name == '__main__' else name))
+
+
+def get_calling_module_object_and_name() -> _ModuleObjectAndName:
+  """Returns the module that's calling into this module.
+
+  We generally use this function to get the name of the module calling a
+  DEFINE_foo... function.
+
+  Returns:
+    The module object that called into this one.
+
+  Raises:
+    AssertionError: Raised when no calling module could be identified.
+  """
+  for depth in range(1, sys.getrecursionlimit()):
+    # sys._getframe is the right thing to use here, as it's the best
+    # way to walk up the call stack.
+    globals_for_frame = sys._getframe(depth).f_globals  # pylint: disable=protected-access
+    module, module_name = get_module_object_and_name(globals_for_frame)
+    if id(module) not in disclaim_module_ids and module_name is not None:
+      return _ModuleObjectAndName(module, module_name)
+  raise AssertionError('No module was found')
+
+
+def get_calling_module() -> str:
+  """Returns the name of the module that's calling into this module."""
+  return get_calling_module_object_and_name().module_name
+
+
+def create_xml_dom_element(
+    doc: minidom.Document, name: str, value: Any
+) -> minidom.Element:
+  """Returns an XML DOM element with name and text value.
+
+  Args:
+    doc: minidom.Document, the DOM document it should create nodes from.
+    name: str, the tag of XML element.
+    value: object, whose string representation will be used
+        as the value of the XML element. Illegal or highly discouraged xml 1.0
+        characters are stripped.
+
+  Returns:
+    An instance of minidom.Element.
+  """
+  s = str(value)
+  if isinstance(value, bool):
+    # Display boolean values as the C++ flag library does: no caps.
+    s = s.lower()
+  # Remove illegal xml characters.
+  s = _ILLEGAL_XML_CHARS_REGEX.sub(u'', s)
+
+  e = doc.createElement(name)
+  e.appendChild(doc.createTextNode(s))
+  return e
+
+
+def get_help_width() -> int:
+  """Returns the integer width of help lines that is used in TextWrap."""
+  if not sys.stdout.isatty() or termios is None or fcntl is None:
+    return _DEFAULT_HELP_WIDTH
+  try:
+    data = fcntl.ioctl(sys.stdout, termios.TIOCGWINSZ, b'1234')
+    columns = struct.unpack('hh', data)[1]
+    # Emacs mode returns 0.
+    # Here we assume that any value below 40 is unreasonable.
+    if columns >= _MIN_HELP_WIDTH:
+      return columns
+    # Returning an int as default is fine, int(int) just return the int.
+    return int(os.getenv('COLUMNS', _DEFAULT_HELP_WIDTH))
+
+  except (TypeError, IOError, struct.error):
+    return _DEFAULT_HELP_WIDTH
+
+
+def get_flag_suggestions(
+    attempt: Optional[str], longopt_list: Sequence[str]
+) -> List[str]:
+  """Returns helpful similar matches for an invalid flag."""
+  # Don't suggest on very short strings, or if no longopts are specified.
+  if len(attempt) <= 2 or not longopt_list:
+    return []
+
+  option_names = [v.split('=')[0] for v in longopt_list]
+
+  # Find close approximations in flag prefixes.
+  # This also handles the case where the flag is spelled right but ambiguous.
+  distances = [(_damerau_levenshtein(attempt, option[0:len(attempt)]), option)
+               for option in option_names]
+  # t[0] is distance, and sorting by t[1] allows us to have stable output.
+  distances.sort()
+
+  least_errors, _ = distances[0]
+  # Don't suggest excessively bad matches.
+  if least_errors >= _SUGGESTION_ERROR_RATE_THRESHOLD * len(attempt):
+    return []
+
+  suggestions = []
+  for errors, name in distances:
+    if errors == least_errors:
+      suggestions.append(name)
+    else:
+      break
+  return suggestions
+
+
+def _damerau_levenshtein(a, b):
+  """Returns Damerau-Levenshtein edit distance from a to b."""
+  memo = {}
+
+  def distance(x, y):
+    """Recursively defined string distance with memoization."""
+    if (x, y) in memo:
+      return memo[x, y]
+    if not x:
+      d = len(y)
+    elif not y:
+      d = len(x)
+    else:
+      d = min(
+          distance(x[1:], y) + 1,  # correct an insertion error
+          distance(x, y[1:]) + 1,  # correct a deletion error
+          distance(x[1:], y[1:]) + (x[0] != y[0]))  # correct a wrong character
+      if len(x) >= 2 and len(y) >= 2 and x[0] == y[1] and x[1] == y[0]:
+        # Correct a transposition.
+        t = distance(x[2:], y[2:]) + 1
+        if d > t:
+          d = t
+
+    memo[x, y] = d
+    return d
+  return distance(a, b)
+
+
+def text_wrap(
+    text: str,
+    length: Optional[int] = None,
+    indent: str = '',
+    firstline_indent: Optional[str] = None,
+) -> str:
+  """Wraps a given text to a maximum line length and returns it.
+
+  It turns lines that only contain whitespace into empty lines, keeps new lines,
+  and expands tabs using 4 spaces.
+
+  Args:
+    text: str, text to wrap.
+    length: int, maximum length of a line, includes indentation.
+        If this is None then use get_help_width()
+    indent: str, indent for all but first line.
+    firstline_indent: str, indent for first line; if None, fall back to indent.
+
+  Returns:
+    str, the wrapped text.
+
+  Raises:
+    ValueError: Raised if indent or firstline_indent not shorter than length.
+  """
+  # Get defaults where callee used None
+  if length is None:
+    length = get_help_width()
+  if indent is None:
+    indent = ''
+  if firstline_indent is None:
+    firstline_indent = indent
+
+  if len(indent) >= length:
+    raise ValueError('Length of indent exceeds length')
+  if len(firstline_indent) >= length:
+    raise ValueError('Length of first line indent exceeds length')
+
+  text = text.expandtabs(4)
+
+  result = []
+  # Create one wrapper for the first paragraph and one for subsequent
+  # paragraphs that does not have the initial wrapping.
+  wrapper = textwrap.TextWrapper(
+      width=length, initial_indent=firstline_indent, subsequent_indent=indent)
+  subsequent_wrapper = textwrap.TextWrapper(
+      width=length, initial_indent=indent, subsequent_indent=indent)
+
+  # textwrap does not have any special treatment for newlines. From the docs:
+  # "...newlines may appear in the middle of a line and cause strange output.
+  # For this reason, text should be split into paragraphs (using
+  # str.splitlines() or similar) which are wrapped separately."
+  for paragraph in (p.strip() for p in text.splitlines()):
+    if paragraph:
+      result.extend(wrapper.wrap(paragraph))
+    else:
+      result.append('')  # Keep empty lines.
+    # Replace initial wrapper with wrapper for subsequent paragraphs.
+    wrapper = subsequent_wrapper
+
+  return '\n'.join(result)
+
+
+def flag_dict_to_args(
+    flag_map: Dict[str, Any], multi_flags: Optional[Set[str]] = None
+) -> Iterable[str]:
+  """Convert a dict of values into process call parameters.
+
+  This method is used to convert a dictionary into a sequence of parameters
+  for a binary that parses arguments using this module.
+
+  Args:
+    flag_map: dict, a mapping where the keys are flag names (strings).
+        values are treated according to their type:
+
+        * If value is ``None``, then only the name is emitted.
+        * If value is ``True``, then only the name is emitted.
+        * If value is ``False``, then only the name prepended with 'no' is
+          emitted.
+        * If value is a string then ``--name=value`` is emitted.
+        * If value is a collection, this will emit
+          ``--name=value1,value2,value3``, unless the flag name is in
+          ``multi_flags``, in which case this will emit
+          ``--name=value1 --name=value2 --name=value3``.
+        * Everything else is converted to string an passed as such.
+
+    multi_flags: set, names (strings) of flags that should be treated as
+        multi-flags.
+  Yields:
+    sequence of string suitable for a subprocess execution.
+  """
+  for key, value in flag_map.items():
+    if value is None:
+      yield '--%s' % key
+    elif isinstance(value, bool):
+      if value:
+        yield '--%s' % key
+      else:
+        yield '--no%s' % key
+    elif isinstance(value, (bytes, type(u''))):
+      # We don't want strings to be handled like python collections.
+      yield '--%s=%s' % (key, value)
+    else:
+      # Now we attempt to deal with collections.
+      try:
+        if multi_flags and key in multi_flags:
+          for item in value:
+            yield '--%s=%s' % (key, str(item))
+        else:
+          yield '--%s=%s' % (key, ','.join(str(item) for item in value))
+      except TypeError:
+        # Default case.
+        yield '--%s=%s' % (key, value)
+
+
+def trim_docstring(docstring: str) -> str:
+  """Removes indentation from triple-quoted strings.
+
+  This is the function specified in PEP 257 to handle docstrings:
+  https://www.python.org/dev/peps/pep-0257/.
+
+  Args:
+    docstring: str, a python docstring.
+
+  Returns:
+    str, docstring with indentation removed.
+  """
+  if not docstring:
+    return ''
+
+  # If you've got a line longer than this you have other problems...
+  max_indent = 1 << 29
+
+  # Convert tabs to spaces (following the normal Python rules)
+  # and split into a list of lines:
+  lines = docstring.expandtabs().splitlines()
+
+  # Determine minimum indentation (first line doesn't count):
+  indent = max_indent
+  for line in lines[1:]:
+    stripped = line.lstrip()
+    if stripped:
+      indent = min(indent, len(line) - len(stripped))
+  # Remove indentation (first line is special):
+  trimmed = [lines[0].strip()]
+  if indent < max_indent:
+    for line in lines[1:]:
+      trimmed.append(line[indent:].rstrip())
+  # Strip off trailing and leading blank lines:
+  while trimmed and not trimmed[-1]:
+    trimmed.pop()
+  while trimmed and not trimmed[0]:
+    trimmed.pop(0)
+  # Return a single string:
+  return '\n'.join(trimmed)
+
+
+def doc_to_help(doc: str) -> str:
+  """Takes a __doc__ string and reformats it as help."""
+
+  # Get rid of starting and ending white space. Using lstrip() or even
+  # strip() could drop more than maximum of first line and right space
+  # of last line.
+  doc = doc.strip()
+
+  # Get rid of all empty lines.
+  whitespace_only_line = re.compile('^[ \t]+$', re.M)
+  doc = whitespace_only_line.sub('', doc)
+
+  # Cut out common space at line beginnings.
+  doc = trim_docstring(doc)
+
+  # Just like this module's comment, comments tend to be aligned somehow.
+  # In other words they all start with the same amount of white space.
+  # 1) keep double new lines;
+  # 2) keep ws after new lines if not empty line;
+  # 3) all other new lines shall be changed to a space;
+  # Solution: Match new lines between non white space and replace with space.
+  doc = re.sub(r'(?<=\S)\n(?=\S)', ' ', doc, flags=re.M)
+
+  return doc

rl/Lib/site-packages/absl/flags/_validators.py

@@ -0,0 +1,352 @@
+# Copyright 2017 The Abseil Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Module to enforce different constraints on flags.
+
+Flags validators can be registered using following functions / decorators::
+
+    flags.register_validator
+    @flags.validator
+    flags.register_multi_flags_validator
+    @flags.multi_flags_validator
+
+Three convenience functions are also provided for common flag constraints::
+
+    flags.mark_flag_as_required
+    flags.mark_flags_as_required
+    flags.mark_flags_as_mutual_exclusive
+    flags.mark_bool_flags_as_mutual_exclusive
+
+See their docstring in this module for a usage manual.
+
+Do NOT import this module directly. Import the flags package and use the
+aliases defined at the package level instead.
+"""
+
+import warnings
+
+from absl.flags import _exceptions
+from absl.flags import _flagvalues
+from absl.flags import _validators_classes
+
+
+def register_validator(flag_name,
+                       checker,
+                       message='Flag validation failed',
+                       flag_values=_flagvalues.FLAGS):
+  """Adds a constraint, which will be enforced during program execution.
+
+  The constraint is validated when flags are initially parsed, and after each
+  change of the corresponding flag's value.
+
+  Args:
+    flag_name: str | FlagHolder, name or holder of the flag to be checked.
+        Positional-only parameter.
+    checker: callable, a function to validate the flag.
+
+        * input - A single positional argument: The value of the corresponding
+          flag (string, boolean, etc.  This value will be passed to checker
+          by the library).
+        * output - bool, True if validator constraint is satisfied.
+          If constraint is not satisfied, it should either ``return False`` or
+          ``raise flags.ValidationError(desired_error_message)``.
+
+    message: str, error text to be shown to the user if checker returns False.
+        If checker raises flags.ValidationError, message from the raised
+        error will be shown.
+    flag_values: flags.FlagValues, optional FlagValues instance to validate
+        against.
+
+  Raises:
+    AttributeError: Raised when flag_name is not registered as a valid flag
+        name.
+    ValueError: Raised when flag_values is non-default and does not match the
+        FlagValues of the provided FlagHolder instance.
+  """
+  flag_name, flag_values = _flagvalues.resolve_flag_ref(flag_name, flag_values)
+  v = _validators_classes.SingleFlagValidator(flag_name, checker, message)
+  _add_validator(flag_values, v)
+
+
+def validator(flag_name, message='Flag validation failed',
+              flag_values=_flagvalues.FLAGS):
+  """A function decorator for defining a flag validator.
+
+  Registers the decorated function as a validator for flag_name, e.g.::
+
+      @flags.validator('foo')
+      def _CheckFoo(foo):
+        ...
+
+  See :func:`register_validator` for the specification of checker function.
+
+  Args:
+    flag_name: str | FlagHolder, name or holder of the flag to be checked.
+        Positional-only parameter.
+    message: str, error text to be shown to the user if checker returns False.
+        If checker raises flags.ValidationError, message from the raised
+        error will be shown.
+    flag_values: flags.FlagValues, optional FlagValues instance to validate
+        against.
+  Returns:
+    A function decorator that registers its function argument as a validator.
+  Raises:
+    AttributeError: Raised when flag_name is not registered as a valid flag
+        name.
+  """
+
+  def decorate(function):
+    register_validator(flag_name, function,
+                       message=message,
+                       flag_values=flag_values)
+    return function
+  return decorate
+
+
+def register_multi_flags_validator(flag_names,
+                                   multi_flags_checker,
+                                   message='Flags validation failed',
+                                   flag_values=_flagvalues.FLAGS):
+  """Adds a constraint to multiple flags.
+
+  The constraint is validated when flags are initially parsed, and after each
+  change of the corresponding flag's value.
+
+  Args:
+    flag_names: [str | FlagHolder], a list of the flag names or holders to be
+        checked. Positional-only parameter.
+    multi_flags_checker: callable, a function to validate the flag.
+
+        * input - dict, with keys() being flag_names, and value for each key
+            being the value of the corresponding flag (string, boolean, etc).
+        * output - bool, True if validator constraint is satisfied.
+            If constraint is not satisfied, it should either return False or
+            raise flags.ValidationError.
+
+    message: str, error text to be shown to the user if checker returns False.
+        If checker raises flags.ValidationError, message from the raised
+        error will be shown.
+    flag_values: flags.FlagValues, optional FlagValues instance to validate
+        against.
+
+  Raises:
+    AttributeError: Raised when a flag is not registered as a valid flag name.
+    ValueError: Raised when multiple FlagValues are used in the same
+        invocation. This can occur when FlagHolders have different `_flagvalues`
+        or when str-type flag_names entries are present and the `flag_values`
+        argument does not match that of provided FlagHolder(s).
+  """
+  flag_names, flag_values = _flagvalues.resolve_flag_refs(
+      flag_names, flag_values)
+  v = _validators_classes.MultiFlagsValidator(
+      flag_names, multi_flags_checker, message)
+  _add_validator(flag_values, v)
+
+
+def multi_flags_validator(flag_names,
+                          message='Flag validation failed',
+                          flag_values=_flagvalues.FLAGS):
+  """A function decorator for defining a multi-flag validator.
+
+  Registers the decorated function as a validator for flag_names, e.g.::
+
+      @flags.multi_flags_validator(['foo', 'bar'])
+      def _CheckFooBar(flags_dict):
+        ...
+
+  See :func:`register_multi_flags_validator` for the specification of checker
+  function.
+
+  Args:
+    flag_names: [str | FlagHolder], a list of the flag names or holders to be
+        checked. Positional-only parameter.
+    message: str, error text to be shown to the user if checker returns False.
+        If checker raises flags.ValidationError, message from the raised
+        error will be shown.
+    flag_values: flags.FlagValues, optional FlagValues instance to validate
+        against.
+
+  Returns:
+    A function decorator that registers its function argument as a validator.
+
+  Raises:
+    AttributeError: Raised when a flag is not registered as a valid flag name.
+  """
+
+  def decorate(function):
+    register_multi_flags_validator(flag_names,
+                                   function,
+                                   message=message,
+                                   flag_values=flag_values)
+    return function
+
+  return decorate
+
+
+def mark_flag_as_required(flag_name, flag_values=_flagvalues.FLAGS):
+  """Ensures that flag is not None during program execution.
+
+  Registers a flag validator, which will follow usual validator rules.
+  Important note: validator will pass for any non-``None`` value, such as
+  ``False``, ``0`` (zero), ``''`` (empty string) and so on.
+
+  If your module might be imported by others, and you only wish to make the flag
+  required when the module is directly executed, call this method like this::
+
+      if __name__ == '__main__':
+        flags.mark_flag_as_required('your_flag_name')
+        app.run()
+
+  Args:
+    flag_name: str | FlagHolder, name or holder of the flag.
+        Positional-only parameter.
+    flag_values: flags.FlagValues, optional :class:`~absl.flags.FlagValues`
+        instance where the flag is defined.
+  Raises:
+    AttributeError: Raised when flag_name is not registered as a valid flag
+        name.
+    ValueError: Raised when flag_values is non-default and does not match the
+        FlagValues of the provided FlagHolder instance.
+  """
+  flag_name, flag_values = _flagvalues.resolve_flag_ref(flag_name, flag_values)
+  if flag_values[flag_name].default is not None:
+    warnings.warn(
+        'Flag --%s has a non-None default value; therefore, '
+        'mark_flag_as_required will pass even if flag is not specified in the '
+        'command line!' % flag_name,
+        stacklevel=2)
+  register_validator(
+      flag_name,
+      lambda value: value is not None,
+      message='Flag --{} must have a value other than None.'.format(flag_name),
+      flag_values=flag_values)
+
+
+def mark_flags_as_required(flag_names, flag_values=_flagvalues.FLAGS):
+  """Ensures that flags are not None during program execution.
+
+  If your module might be imported by others, and you only wish to make the flag
+  required when the module is directly executed, call this method like this::
+
+      if __name__ == '__main__':
+        flags.mark_flags_as_required(['flag1', 'flag2', 'flag3'])
+        app.run()
+
+  Args:
+    flag_names: Sequence[str | FlagHolder], names or holders of the flags.
+    flag_values: flags.FlagValues, optional FlagValues instance where the flags
+        are defined.
+  Raises:
+    AttributeError: If any of flag name has not already been defined as a flag.
+  """
+  for flag_name in flag_names:
+    mark_flag_as_required(flag_name, flag_values)
+
+
+def mark_flags_as_mutual_exclusive(flag_names, required=False,
+                                   flag_values=_flagvalues.FLAGS):
+  """Ensures that only one flag among flag_names is not None.
+
+  Important note: This validator checks if flag values are ``None``, and it does
+  not distinguish between default and explicit values. Therefore, this validator
+  does not make sense when applied to flags with default values other than None,
+  including other false values (e.g. ``False``, ``0``, ``''``, ``[]``). That
+  includes multi flags with a default value of ``[]`` instead of None.
+
+  Args:
+    flag_names: [str | FlagHolder], names or holders of flags.
+        Positional-only parameter.
+    required: bool. If true, exactly one of the flags must have a value other
+        than None. Otherwise, at most one of the flags can have a value other
+        than None, and it is valid for all of the flags to be None.
+    flag_values: flags.FlagValues, optional FlagValues instance where the flags
+        are defined.
+
+  Raises:
+    ValueError: Raised when multiple FlagValues are used in the same
+        invocation. This can occur when FlagHolders have different `_flagvalues`
+        or when str-type flag_names entries are present and the `flag_values`
+        argument does not match that of provided FlagHolder(s).
+  """
+  flag_names, flag_values = _flagvalues.resolve_flag_refs(
+      flag_names, flag_values)
+  for flag_name in flag_names:
+    if flag_values[flag_name].default is not None:
+      warnings.warn(
+          'Flag --{} has a non-None default value. That does not make sense '
+          'with mark_flags_as_mutual_exclusive, which checks whether the '
+          'listed flags have a value other than None.'.format(flag_name),
+          stacklevel=2)
+
+  def validate_mutual_exclusion(flags_dict):
+    flag_count = sum(1 for val in flags_dict.values() if val is not None)
+    if flag_count == 1 or (not required and flag_count == 0):
+      return True
+    raise _exceptions.ValidationError(
+        '{} one of ({}) must have a value other than None.'.format(
+            'Exactly' if required else 'At most', ', '.join(flag_names)))
+
+  register_multi_flags_validator(
+      flag_names, validate_mutual_exclusion, flag_values=flag_values)
+
+
+def mark_bool_flags_as_mutual_exclusive(flag_names, required=False,
+                                        flag_values=_flagvalues.FLAGS):
+  """Ensures that only one flag among flag_names is True.
+
+  Args:
+    flag_names: [str | FlagHolder], names or holders of flags.
+        Positional-only parameter.
+    required: bool. If true, exactly one flag must be True. Otherwise, at most
+        one flag can be True, and it is valid for all flags to be False.
+    flag_values: flags.FlagValues, optional FlagValues instance where the flags
+        are defined.
+
+  Raises:
+    ValueError: Raised when multiple FlagValues are used in the same
+        invocation. This can occur when FlagHolders have different `_flagvalues`
+        or when str-type flag_names entries are present and the `flag_values`
+        argument does not match that of provided FlagHolder(s).
+  """
+  flag_names, flag_values = _flagvalues.resolve_flag_refs(
+      flag_names, flag_values)
+  for flag_name in flag_names:
+    if not flag_values[flag_name].boolean:
+      raise _exceptions.ValidationError(
+          'Flag --{} is not Boolean, which is required for flags used in '
+          'mark_bool_flags_as_mutual_exclusive.'.format(flag_name))
+
+  def validate_boolean_mutual_exclusion(flags_dict):
+    flag_count = sum(bool(val) for val in flags_dict.values())
+    if flag_count == 1 or (not required and flag_count == 0):
+      return True
+    raise _exceptions.ValidationError(
+        '{} one of ({}) must be True.'.format(
+            'Exactly' if required else 'At most', ', '.join(flag_names)))
+
+  register_multi_flags_validator(
+      flag_names, validate_boolean_mutual_exclusion, flag_values=flag_values)
+
+
+def _add_validator(fv, validator_instance):
+  """Register new flags validator to be checked.
+
+  Args:
+    fv: flags.FlagValues, the FlagValues instance to add the validator.
+    validator_instance: validators.Validator, the validator to add.
+  Raises:
+    KeyError: Raised when validators work with a non-existing flag.
+  """
+  for flag_name in validator_instance.get_flags_names():
+    fv[flag_name].validators.append(validator_instance)

rl/Lib/site-packages/absl/flags/_validators_classes.py

@@ -0,0 +1,172 @@
+# Copyright 2021 The Abseil Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Defines *private* classes used for flag validators.
+
+Do NOT import this module. DO NOT use anything from this module. They are
+private APIs.
+"""
+
+from absl.flags import _exceptions
+
+
+class Validator(object):
+  """Base class for flags validators.
+
+  Users should NOT overload these classes, and use flags.Register...
+  methods instead.
+  """
+
+  # Used to assign each validator an unique insertion_index
+  validators_count = 0
+
+  def __init__(self, checker, message):
+    """Constructor to create all validators.
+
+    Args:
+      checker: function to verify the constraint.
+          Input of this method varies, see SingleFlagValidator and
+          multi_flags_validator for a detailed description.
+      message: str, error message to be shown to the user.
+    """
+    self.checker = checker
+    self.message = message
+    Validator.validators_count += 1
+    # Used to assert validators in the order they were registered.
+    self.insertion_index = Validator.validators_count
+
+  def verify(self, flag_values):
+    """Verifies that constraint is satisfied.
+
+    flags library calls this method to verify Validator's constraint.
+
+    Args:
+      flag_values: flags.FlagValues, the FlagValues instance to get flags from.
+    Raises:
+      Error: Raised if constraint is not satisfied.
+    """
+    param = self._get_input_to_checker_function(flag_values)
+    if not self.checker(param):
+      raise _exceptions.ValidationError(self.message)
+
+  def get_flags_names(self):
+    """Returns the names of the flags checked by this validator.
+
+    Returns:
+      [string], names of the flags.
+    """
+    raise NotImplementedError('This method should be overloaded')
+
+  def print_flags_with_values(self, flag_values):
+    raise NotImplementedError('This method should be overloaded')
+
+  def _get_input_to_checker_function(self, flag_values):
+    """Given flag values, returns the input to be given to checker.
+
+    Args:
+      flag_values: flags.FlagValues, containing all flags.
+    Returns:
+      The input to be given to checker. The return type depends on the specific
+      validator.
+    """
+    raise NotImplementedError('This method should be overloaded')
+
+
+class SingleFlagValidator(Validator):
+  """Validator behind register_validator() method.
+
+  Validates that a single flag passes its checker function. The checker function
+  takes the flag value and returns True (if value looks fine) or, if flag value
+  is not valid, either returns False or raises an Exception.
+  """
+
+  def __init__(self, flag_name, checker, message):
+    """Constructor.
+
+    Args:
+      flag_name: string, name of the flag.
+      checker: function to verify the validator.
+          input  - value of the corresponding flag (string, boolean, etc).
+          output - bool, True if validator constraint is satisfied.
+              If constraint is not satisfied, it should either return False or
+              raise flags.ValidationError(desired_error_message).
+      message: str, error message to be shown to the user if validator's
+          condition is not satisfied.
+    """
+    super(SingleFlagValidator, self).__init__(checker, message)
+    self.flag_name = flag_name
+
+  def get_flags_names(self):
+    return [self.flag_name]
+
+  def print_flags_with_values(self, flag_values):
+    return 'flag --%s=%s' % (self.flag_name, flag_values[self.flag_name].value)
+
+  def _get_input_to_checker_function(self, flag_values):
+    """Given flag values, returns the input to be given to checker.
+
+    Args:
+      flag_values: flags.FlagValues, the FlagValues instance to get flags from.
+    Returns:
+      object, the input to be given to checker.
+    """
+    return flag_values[self.flag_name].value
+
+
+class MultiFlagsValidator(Validator):
+  """Validator behind register_multi_flags_validator method.
+
+  Validates that flag values pass their common checker function. The checker
+  function takes flag values and returns True (if values look fine) or,
+  if values are not valid, either returns False or raises an Exception.
+  """
+
+  def __init__(self, flag_names, checker, message):
+    """Constructor.
+
+    Args:
+      flag_names: [str], containing names of the flags used by checker.
+      checker: function to verify the validator.
+          input  - dict, with keys() being flag_names, and value for each
+              key being the value of the corresponding flag (string, boolean,
+              etc).
+          output - bool, True if validator constraint is satisfied.
+              If constraint is not satisfied, it should either return False or
+              raise flags.ValidationError(desired_error_message).
+      message: str, error message to be shown to the user if validator's
+          condition is not satisfied
+    """
+    super(MultiFlagsValidator, self).__init__(checker, message)
+    self.flag_names = flag_names
+
+  def _get_input_to_checker_function(self, flag_values):
+    """Given flag values, returns the input to be given to checker.
+
+    Args:
+      flag_values: flags.FlagValues, the FlagValues instance to get flags from.
+    Returns:
+      dict, with keys() being self.flag_names, and value for each key
+      being the value of the corresponding flag (string, boolean, etc).
+    """
+    return dict([key, flag_values[key].value] for key in self.flag_names)
+
+  def print_flags_with_values(self, flag_values):
+    prefix = 'flags '
+    flags_with_values = []
+    for key in self.flag_names:
+      flags_with_values.append('%s=%s' % (key, flag_values[key].value))
+    return prefix + ', '.join(flags_with_values)
+
+  def get_flags_names(self):
+    return self.flag_names

rl/Lib/site-packages/absl/flags/argparse_flags.py

@@ -0,0 +1,388 @@
+# Copyright 2018 The Abseil Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""This module provides argparse integration with absl.flags.
+
+``argparse_flags.ArgumentParser`` is a drop-in replacement for
+:class:`argparse.ArgumentParser`. It takes care of collecting and defining absl
+flags in :mod:`argparse`.
+
+Here is a simple example::
+
+    # Assume the following absl.flags is defined in another module:
+    #
+    #     from absl import flags
+    #     flags.DEFINE_string('echo', None, 'The echo message.')
+    #
+    parser = argparse_flags.ArgumentParser(
+        description='A demo of absl.flags and argparse integration.')
+    parser.add_argument('--header', help='Header message to print.')
+
+    # The parser will also accept the absl flag `--echo`.
+    # The `header` value is available as `args.header` just like a regular
+    # argparse flag. The absl flag `--echo` continues to be available via
+    # `absl.flags.FLAGS` if you want to access it.
+    args = parser.parse_args()
+
+    # Example usages:
+    # ./program --echo='A message.' --header='A header'
+    # ./program --header 'A header' --echo 'A message.'
+
+
+Here is another example demonstrates subparsers::
+
+    parser = argparse_flags.ArgumentParser(description='A subcommands demo.')
+    parser.add_argument('--header', help='The header message to print.')
+
+    subparsers = parser.add_subparsers(help='The command to execute.')
+
+    roll_dice_parser = subparsers.add_parser(
+        'roll_dice', help='Roll a dice.',
+        # By default, absl flags can also be specified after the sub-command.
+        # To only allow them before sub-command, pass
+        # `inherited_absl_flags=None`.
+        inherited_absl_flags=None)
+    roll_dice_parser.add_argument('--num_faces', type=int, default=6)
+    roll_dice_parser.set_defaults(command=roll_dice)
+
+    shuffle_parser = subparsers.add_parser('shuffle', help='Shuffle inputs.')
+    shuffle_parser.add_argument(
+        'inputs', metavar='I', nargs='+', help='Inputs to shuffle.')
+    shuffle_parser.set_defaults(command=shuffle)
+
+    args = parser.parse_args(argv[1:])
+    args.command(args)
+
+    # Example usages:
+    # ./program --echo='A message.' roll_dice --num_faces=6
+    # ./program shuffle --echo='A message.' 1 2 3 4
+
+
+There are several differences between :mod:`absl.flags` and
+:mod:`~absl.flags.argparse_flags`:
+
+1. Flags defined with absl.flags are parsed differently when using the
+   argparse parser. Notably:
+
+   1) absl.flags allows both single-dash and double-dash for any flag, and
+      doesn't distinguish them; argparse_flags only allows double-dash for
+      flag's regular name, and single-dash for flag's ``short_name``.
+   2) Boolean flags in absl.flags can be specified with ``--bool``,
+      ``--nobool``, as well as ``--bool=true/false`` (though not recommended);
+      in argparse_flags, it only allows ``--bool``, ``--nobool``.
+
+2. Help related flag differences:
+
+   1) absl.flags does not define help flags, absl.app does that; argparse_flags
+      defines help flags unless passed with ``add_help=False``.
+   2) absl.app supports ``--helpxml``; argparse_flags does not.
+   3) argparse_flags supports ``-h``; absl.app does not.
+"""
+
+import argparse
+import sys
+
+from absl import flags
+
+
+_BUILT_IN_FLAGS = frozenset({
+    'help',
+    'helpshort',
+    'helpfull',
+    'helpxml',
+    'flagfile',
+    'undefok',
+})
+
+
+class ArgumentParser(argparse.ArgumentParser):
+  """Custom ArgumentParser class to support special absl flags."""
+
+  def __init__(self, **kwargs):
+    """Initializes ArgumentParser.
+
+    Args:
+      **kwargs: same as argparse.ArgumentParser, except:
+          1. It also accepts `inherited_absl_flags`: the absl flags to inherit.
+             The default is the global absl.flags.FLAGS instance. Pass None to
+             ignore absl flags.
+          2. The `prefix_chars` argument must be the default value '-'.
+
+    Raises:
+      ValueError: Raised when prefix_chars is not '-'.
+    """
+    prefix_chars = kwargs.get('prefix_chars', '-')
+    if prefix_chars != '-':
+      raise ValueError(
+          'argparse_flags.ArgumentParser only supports "-" as the prefix '
+          'character, found "{}".'.format(prefix_chars))
+
+    # Remove inherited_absl_flags before calling super.
+    self._inherited_absl_flags = kwargs.pop('inherited_absl_flags', flags.FLAGS)
+    # Now call super to initialize argparse.ArgumentParser before calling
+    # add_argument in _define_absl_flags.
+    super(ArgumentParser, self).__init__(**kwargs)
+
+    if self.add_help:
+      # -h and --help are defined in super.
+      # Also add the --helpshort and --helpfull flags.
+      self.add_argument(
+          # Action 'help' defines a similar flag to -h/--help.
+          '--helpshort', action='help',
+          default=argparse.SUPPRESS, help=argparse.SUPPRESS)
+      self.add_argument(
+          '--helpfull', action=_HelpFullAction,
+          default=argparse.SUPPRESS, help='show full help message and exit')
+
+    if self._inherited_absl_flags is not None:
+      self.add_argument(
+          '--undefok', default=argparse.SUPPRESS, help=argparse.SUPPRESS)
+      self._define_absl_flags(self._inherited_absl_flags)
+
+  def parse_known_args(self, args=None, namespace=None):
+    if args is None:
+      args = sys.argv[1:]
+    if self._inherited_absl_flags is not None:
+      # Handle --flagfile.
+      # Explicitly specify force_gnu=True, since argparse behaves like
+      # gnu_getopt: flags can be specified after positional arguments.
+      args = self._inherited_absl_flags.read_flags_from_files(
+          args, force_gnu=True)
+
+    undefok_missing = object()
+    undefok = getattr(namespace, 'undefok', undefok_missing)
+
+    namespace, args = super(ArgumentParser, self).parse_known_args(
+        args, namespace)
+
+    # For Python <= 2.7.8: https://bugs.python.org/issue9351, a bug where
+    # sub-parsers don't preserve existing namespace attributes.
+    # Restore the undefok attribute if a sub-parser dropped it.
+    if undefok is not undefok_missing:
+      namespace.undefok = undefok
+
+    if self._inherited_absl_flags is not None:
+      # Handle --undefok. At this point, `args` only contains unknown flags,
+      # so it won't strip defined flags that are also specified with --undefok.
+      # For Python <= 2.7.8: https://bugs.python.org/issue9351, a bug where
+      # sub-parsers don't preserve existing namespace attributes. The undefok
+      # attribute might not exist because a subparser dropped it.
+      if hasattr(namespace, 'undefok'):
+        args = _strip_undefok_args(namespace.undefok, args)
+        # absl flags are not exposed in the Namespace object. See Namespace:
+        # https://docs.python.org/3/library/argparse.html#argparse.Namespace.
+        del namespace.undefok
+      self._inherited_absl_flags.mark_as_parsed()
+      try:
+        self._inherited_absl_flags.validate_all_flags()
+      except flags.IllegalFlagValueError as e:
+        self.error(str(e))
+
+    return namespace, args
+
+  def _define_absl_flags(self, absl_flags):
+    """Defines flags from absl_flags."""
+    key_flags = set(absl_flags.get_key_flags_for_module(sys.argv[0]))
+    for name in absl_flags:
+      if name in _BUILT_IN_FLAGS:
+        # Do not inherit built-in flags.
+        continue
+      flag_instance = absl_flags[name]
+      # Each flags with short_name appears in FLAGS twice, so only define
+      # when the dictionary key is equal to the regular name.
+      if name == flag_instance.name:
+        # Suppress the flag in the help short message if it's not a main
+        # module's key flag.
+        suppress = flag_instance not in key_flags
+        self._define_absl_flag(flag_instance, suppress)
+
+  def _define_absl_flag(self, flag_instance, suppress):
+    """Defines a flag from the flag_instance."""
+    flag_name = flag_instance.name
+    short_name = flag_instance.short_name
+    argument_names = ['--' + flag_name]
+    if short_name:
+      argument_names.insert(0, '-' + short_name)
+    if suppress:
+      helptext = argparse.SUPPRESS
+    else:
+      # argparse help string uses %-formatting. Escape the literal %'s.
+      helptext = flag_instance.help.replace('%', '%%')
+    if flag_instance.boolean:
+      # Only add the `no` form to the long name.
+      argument_names.append('--no' + flag_name)
+      self.add_argument(
+          *argument_names, action=_BooleanFlagAction, help=helptext,
+          metavar=flag_instance.name.upper(),
+          flag_instance=flag_instance)
+    else:
+      self.add_argument(
+          *argument_names, action=_FlagAction, help=helptext,
+          metavar=flag_instance.name.upper(),
+          flag_instance=flag_instance)
+
+
+class _FlagAction(argparse.Action):
+  """Action class for Abseil non-boolean flags."""
+
+  def __init__(
+      self,
+      option_strings,
+      dest,
+      help,  # pylint: disable=redefined-builtin
+      metavar,
+      flag_instance,
+      default=argparse.SUPPRESS):
+    """Initializes _FlagAction.
+
+    Args:
+      option_strings: See argparse.Action.
+      dest: Ignored. The flag is always defined with dest=argparse.SUPPRESS.
+      help: See argparse.Action.
+      metavar: See argparse.Action.
+      flag_instance: absl.flags.Flag, the absl flag instance.
+      default: Ignored. The flag always uses dest=argparse.SUPPRESS so it
+          doesn't affect the parsing result.
+    """
+    del dest
+    self._flag_instance = flag_instance
+    super(_FlagAction, self).__init__(
+        option_strings=option_strings,
+        dest=argparse.SUPPRESS,
+        help=help,
+        metavar=metavar)
+
+  def __call__(self, parser, namespace, values, option_string=None):
+    """See https://docs.python.org/3/library/argparse.html#action-classes."""
+    self._flag_instance.parse(values)
+    self._flag_instance.using_default_value = False
+
+
+class _BooleanFlagAction(argparse.Action):
+  """Action class for Abseil boolean flags."""
+
+  def __init__(
+      self,
+      option_strings,
+      dest,
+      help,  # pylint: disable=redefined-builtin
+      metavar,
+      flag_instance,
+      default=argparse.SUPPRESS):
+    """Initializes _BooleanFlagAction.
+
+    Args:
+      option_strings: See argparse.Action.
+      dest: Ignored. The flag is always defined with dest=argparse.SUPPRESS.
+      help: See argparse.Action.
+      metavar: See argparse.Action.
+      flag_instance: absl.flags.Flag, the absl flag instance.
+      default: Ignored. The flag always uses dest=argparse.SUPPRESS so it
+          doesn't affect the parsing result.
+    """
+    del dest, default
+    self._flag_instance = flag_instance
+    flag_names = [self._flag_instance.name]
+    if self._flag_instance.short_name:
+      flag_names.append(self._flag_instance.short_name)
+    self._flag_names = frozenset(flag_names)
+    super(_BooleanFlagAction, self).__init__(
+        option_strings=option_strings,
+        dest=argparse.SUPPRESS,
+        nargs=0,  # Does not accept values, only `--bool` or `--nobool`.
+        help=help,
+        metavar=metavar)
+
+  def __call__(self, parser, namespace, values, option_string=None):
+    """See https://docs.python.org/3/library/argparse.html#action-classes."""
+    if not isinstance(values, list) or values:
+      raise ValueError('values must be an empty list.')
+    if option_string.startswith('--'):
+      option = option_string[2:]
+    else:
+      option = option_string[1:]
+    if option in self._flag_names:
+      self._flag_instance.parse('true')
+    else:
+      if not option.startswith('no') or option[2:] not in self._flag_names:
+        raise ValueError('invalid option_string: ' + option_string)
+      self._flag_instance.parse('false')
+    self._flag_instance.using_default_value = False
+
+
+class _HelpFullAction(argparse.Action):
+  """Action class for --helpfull flag."""
+
+  def __init__(self, option_strings, dest, default, help):  # pylint: disable=redefined-builtin
+    """Initializes _HelpFullAction.
+
+    Args:
+      option_strings: See argparse.Action.
+      dest: Ignored. The flag is always defined with dest=argparse.SUPPRESS.
+      default: Ignored.
+      help: See argparse.Action.
+    """
+    del dest, default
+    super(_HelpFullAction, self).__init__(
+        option_strings=option_strings,
+        dest=argparse.SUPPRESS,
+        default=argparse.SUPPRESS,
+        nargs=0,
+        help=help)
+
+  def __call__(self, parser, namespace, values, option_string=None):
+    """See https://docs.python.org/3/library/argparse.html#action-classes."""
+    # This only prints flags when help is not argparse.SUPPRESS.
+    # It includes user defined argparse flags, as well as main module's
+    # key absl flags. Other absl flags use argparse.SUPPRESS, so they aren't
+    # printed here.
+    parser.print_help()
+
+    absl_flags = parser._inherited_absl_flags  # pylint: disable=protected-access
+    if absl_flags is not None:
+      modules = sorted(absl_flags.flags_by_module_dict())
+      main_module = sys.argv[0]
+      if main_module in modules:
+        # The main module flags are already printed in parser.print_help().
+        modules.remove(main_module)
+      print(absl_flags._get_help_for_modules(  # pylint: disable=protected-access
+          modules, prefix='', include_special_flags=True))
+    parser.exit()
+
+
+def _strip_undefok_args(undefok, args):
+  """Returns a new list of args after removing flags in --undefok."""
+  if undefok:
+    undefok_names = set(name.strip() for name in undefok.split(','))
+    undefok_names |= set('no' + name for name in undefok_names)
+    # Remove undefok flags.
+    args = [arg for arg in args if not _is_undefok(arg, undefok_names)]
+  return args
+
+
+def _is_undefok(arg, undefok_names):
+  """Returns whether we can ignore arg based on a set of undefok flag names."""
+  if not arg.startswith('-'):
+    return False
+  if arg.startswith('--'):
+    arg_without_dash = arg[2:]
+  else:
+    arg_without_dash = arg[1:]
+  if '=' in arg_without_dash:
+    name, _ = arg_without_dash.split('=', 1)
+  else:
+    name = arg_without_dash
+  if name in undefok_names:
+    return True
+  return False