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rl/Lib/site-packages/torch/fx/experimental/unification/__init__.py

@@ -0,0 +1,4 @@
+# mypy: disable-error-code=attr-defined
+from .core import unify, reify  # noqa: F403
+from .more import unifiable  # noqa: F403
+from .variable import var, isvar, vars, variables, Var  # noqa: F403

rl/Lib/site-packages/torch/fx/experimental/unification/core.py

@@ -0,0 +1,119 @@
+# mypy: allow-untyped-defs
+from collections.abc import Iterator  # type: ignore[import]
+from functools import partial
+
+from .unification_tools import assoc  # type: ignore[import]
+from .utils import transitive_get as walk
+from .variable import isvar
+from .dispatch import dispatch
+
+__all__ = ["reify", "unify"]
+
+###############
+# Reification #
+###############
+
+@dispatch(Iterator, dict)
+def _reify(t, s):
+    return map(partial(reify, s=s), t)
+    # return (reify(arg, s) for arg in t)
+_reify
+
+@dispatch(tuple, dict)  # type: ignore[no-redef]
+def _reify(t, s):
+    return tuple(reify(iter(t), s))
+_reify
+
+@dispatch(list, dict)  # type: ignore[no-redef]
+def _reify(t, s):
+    return list(reify(iter(t), s))
+_reify
+
+@dispatch(dict, dict)  # type: ignore[no-redef]
+def _reify(d, s):
+    return {k: reify(v, s) for k, v in d.items()}
+_reify
+
+@dispatch(object, dict)  # type: ignore[no-redef]
+def _reify(o, s):
+    return o  # catch all, just return the object
+
+def reify(e, s):
+    """ Replace variables of expression with substitution
+    >>> # xdoctest: +SKIP
+    >>> x, y = var(), var()
+    >>> e = (1, x, (3, y))
+    >>> s = {x: 2, y: 4}
+    >>> reify(e, s)
+    (1, 2, (3, 4))
+    >>> e = {1: x, 3: (y, 5)}
+    >>> reify(e, s)
+    {1: 2, 3: (4, 5)}
+    """
+    if isvar(e):
+        return reify(s[e], s) if e in s else e
+    return _reify(e, s)
+
+###############
+# Unification #
+###############
+
+seq = tuple, list, Iterator
+
+@dispatch(seq, seq, dict)
+def _unify(u, v, s):
+    if len(u) != len(v):
+        return False
+    for uu, vv in zip(u, v):  # avoiding recursion
+        s = unify(uu, vv, s)
+        if s is False:
+            return False
+    return s
+#
+# @dispatch((set, frozenset), (set, frozenset), dict)
+# def _unify(u, v, s):
+#     i = u & v
+#     u = u - i
+#     v = v - i
+#     return _unify(sorted(u), sorted(v), s)
+#
+#
+# @dispatch(dict, dict, dict)
+# def _unify(u, v, s):
+#     if len(u) != len(v):
+#         return False
+#     for key, uval in iteritems(u):
+#         if key not in v:
+#             return False
+#         s = unify(uval, v[key], s)
+#         if s is False:
+#             return False
+#     return s
+#
+#
+# @dispatch(object, object, dict)
+# def _unify(u, v, s):
+#     return False  # catch all
+
+
+@dispatch(object, object, dict)
+def unify(u, v, s):  # no check at the moment
+    """ Find substitution so that u == v while satisfying s
+    >>> x = var('x')
+    >>> unify((1, x), (1, 2), {})
+    {~x: 2}
+    """
+    u = walk(u, s)
+    v = walk(v, s)
+    if u == v:
+        return s
+    if isvar(u):
+        return assoc(s, u, v)
+    if isvar(v):
+        return assoc(s, v, u)
+    return _unify(u, v, s)
+unify
+
+@dispatch(object, object)  # type: ignore[no-redef]
+def unify(u, v):
+    return unify(u, v, {})

rl/Lib/site-packages/torch/fx/experimental/unification/dispatch.py

@@ -0,0 +1,6 @@
+from functools import partial
+from .multipledispatch import dispatch  # type: ignore[import]
+
+namespace = {}  # type: ignore[var-annotated]
+
+dispatch = partial(dispatch, namespace=namespace)

rl/Lib/site-packages/torch/fx/experimental/unification/match.py

@@ -0,0 +1,122 @@
+# mypy: allow-untyped-defs
+from .core import unify, reify  # type: ignore[attr-defined]
+from .variable import isvar
+from .utils import _toposort, freeze
+from .unification_tools import groupby, first  # type: ignore[import]
+
+
+class Dispatcher:
+    def __init__(self, name):
+        self.name = name
+        self.funcs = {}
+        self.ordering = []
+
+    def add(self, signature, func):
+        self.funcs[freeze(signature)] = func
+        self.ordering = ordering(self.funcs)
+
+    def __call__(self, *args, **kwargs):
+        func, s = self.resolve(args)
+        return func(*args, **kwargs)
+
+    def resolve(self, args):
+        n = len(args)
+        for signature in self.ordering:
+            if len(signature) != n:
+                continue
+            s = unify(freeze(args), signature)
+            if s is not False:
+                result = self.funcs[signature]
+                return result, s
+        raise NotImplementedError("No match found. \nKnown matches: "
+                                  + str(self.ordering) + "\nInput: " + str(args))
+
+    def register(self, *signature):
+        def _(func):
+            self.add(signature, func)
+            return self
+        return _
+
+
+class VarDispatcher(Dispatcher):
+    """ A dispatcher that calls functions with variable names
+    >>> # xdoctest: +SKIP
+    >>> d = VarDispatcher('d')
+    >>> x = var('x')
+    >>> @d.register('inc', x)
+    ... def f(x):
+    ...     return x + 1
+    >>> @d.register('double', x)
+    ... def f(x):
+    ...     return x * 2
+    >>> d('inc', 10)
+    11
+    >>> d('double', 10)
+    20
+    """
+    def __call__(self, *args, **kwargs):
+        func, s = self.resolve(args)
+        d = {k.token: v for k, v in s.items()}
+        return func(**d)
+
+
+global_namespace = {}  # type: ignore[var-annotated]
+
+
+def match(*signature, **kwargs):
+    namespace = kwargs.get('namespace', global_namespace)
+    dispatcher = kwargs.get('Dispatcher', Dispatcher)
+
+    def _(func):
+        name = func.__name__
+
+        if name not in namespace:
+            namespace[name] = dispatcher(name)
+        d = namespace[name]
+
+        d.add(signature, func)
+
+        return d
+    return _
+
+
+def supercedes(a, b):
+    """ ``a`` is a more specific match than ``b`` """
+    if isvar(b) and not isvar(a):
+        return True
+    s = unify(a, b)
+    if s is False:
+        return False
+    s = {k: v for k, v in s.items() if not isvar(k) or not isvar(v)}
+    if reify(a, s) == a:
+        return True
+    if reify(b, s) == b:
+        return False
+
+
+# Taken from multipledispatch
+def edge(a, b, tie_breaker=hash):
+    """ A should be checked before B
+    Tie broken by tie_breaker, defaults to ``hash``
+    """
+    if supercedes(a, b):
+        if supercedes(b, a):
+            return tie_breaker(a) > tie_breaker(b)
+        else:
+            return True
+    return False
+
+
+# Taken from multipledispatch
+def ordering(signatures):
+    """ A sane ordering of signatures to check, first to last
+    Topological sort of edges as given by ``edge`` and ``supercedes``
+    """
+    signatures = list(map(tuple, signatures))
+    edges = [(a, b) for a in signatures for b in signatures if edge(a, b)]
+    edges = groupby(first, edges)
+    for s in signatures:
+        if s not in edges:
+            edges[s] = []
+    edges = {k: [b for a, b in v] for k, v in edges.items()}  # type: ignore[attr-defined, assignment]
+    return _toposort(edges)

rl/Lib/site-packages/torch/fx/experimental/unification/more.py

@@ -0,0 +1,118 @@
+# mypy: allow-untyped-defs
+from .core import unify, reify  # type: ignore[attr-defined]
+from .dispatch import dispatch
+
+
+def unifiable(cls):
+    """ Register standard unify and reify operations on class
+    This uses the type and __dict__ or __slots__ attributes to define the
+    nature of the term
+    See Also:
+    >>> # xdoctest: +SKIP
+    >>> class A(object):
+    ...     def __init__(self, a, b):
+    ...         self.a = a
+    ...         self.b = b
+    >>> unifiable(A)
+    <class 'unification.more.A'>
+    >>> x = var('x')
+    >>> a = A(1, 2)
+    >>> b = A(1, x)
+    >>> unify(a, b, {})
+    {~x: 2}
+    """
+    _unify.add((cls, cls, dict), unify_object)
+    _reify.add((cls, dict), reify_object)
+
+    return cls
+
+
+#########
+# Reify #
+#########
+
+
+def reify_object(o, s):
+    """ Reify a Python object with a substitution
+    >>> # xdoctest: +SKIP
+    >>> class Foo(object):
+    ...     def __init__(self, a, b):
+    ...         self.a = a
+    ...         self.b = b
+    ...     def __str__(self):
+    ...         return "Foo(%s, %s)"%(str(self.a), str(self.b))
+    >>> x = var('x')
+    >>> f = Foo(1, x)
+    >>> print(f)
+    Foo(1, ~x)
+    >>> print(reify_object(f, {x: 2}))
+    Foo(1, 2)
+    """
+    if hasattr(o, '__slots__'):
+        return _reify_object_slots(o, s)
+    else:
+        return _reify_object_dict(o, s)
+
+
+def _reify_object_dict(o, s):
+    obj = object.__new__(type(o))
+    d = reify(o.__dict__, s)
+    if d == o.__dict__:
+        return o
+    obj.__dict__.update(d)
+    return obj
+
+
+def _reify_object_slots(o, s):
+    attrs = [getattr(o, attr) for attr in o.__slots__]
+    new_attrs = reify(attrs, s)
+    if attrs == new_attrs:
+        return o
+    else:
+        newobj = object.__new__(type(o))
+        for slot, attr in zip(o.__slots__, new_attrs):
+            setattr(newobj, slot, attr)
+        return newobj
+
+
+@dispatch(slice, dict)
+def _reify(o, s):
+    """ Reify a Python ``slice`` object """
+    return slice(*reify((o.start, o.stop, o.step), s))
+
+
+#########
+# Unify #
+#########
+
+
+def unify_object(u, v, s):
+    """ Unify two Python objects
+    Unifies their type and ``__dict__`` attributes
+    >>> # xdoctest: +SKIP
+    >>> class Foo(object):
+    ...     def __init__(self, a, b):
+    ...         self.a = a
+    ...         self.b = b
+    ...     def __str__(self):
+    ...         return "Foo(%s, %s)"%(str(self.a), str(self.b))
+    >>> x = var('x')
+    >>> f = Foo(1, x)
+    >>> g = Foo(1, 2)
+    >>> unify_object(f, g, {})
+    {~x: 2}
+    """
+    if type(u) != type(v):
+        return False
+    if hasattr(u, '__slots__'):
+        return unify([getattr(u, slot) for slot in u.__slots__],
+                     [getattr(v, slot) for slot in v.__slots__],
+                     s)
+    else:
+        return unify(u.__dict__, v.__dict__, s)
+
+
+@dispatch(slice, slice, dict)
+def _unify(u, v, s):
+    """ Unify a Python ``slice`` object """
+    return unify((u.start, u.stop, u.step), (v.start, v.stop, v.step), s)

rl/Lib/site-packages/torch/fx/experimental/unification/multipledispatch/__init__.py

@@ -0,0 +1,3 @@
+from .core import dispatch
+from .dispatcher import (Dispatcher, halt_ordering, restart_ordering,
+                         MDNotImplementedError)

rl/Lib/site-packages/torch/fx/experimental/unification/multipledispatch/conflict.py

@@ -0,0 +1,121 @@
+# mypy: allow-untyped-defs
+from .utils import _toposort, groupby
+from .variadic import isvariadic
+import operator
+
+__all__ = ["AmbiguityWarning", "supercedes", "consistent", "ambiguous", "ambiguities", "super_signature",
+           "edge", "ordering"]
+
+class AmbiguityWarning(Warning):
+    pass
+
+
+def supercedes(a, b):
+    """ A is consistent and strictly more specific than B """
+    if len(a) < len(b):
+        # only case is if a is empty and b is variadic
+        return not a and len(b) == 1 and isvariadic(b[-1])
+    elif len(a) == len(b):
+        return all(map(issubclass, a, b))
+    else:
+        # len(a) > len(b)
+        p1 = 0
+        p2 = 0
+        while p1 < len(a) and p2 < len(b):
+            cur_a = a[p1]
+            cur_b = b[p2]
+            if not (isvariadic(cur_a) or isvariadic(cur_b)):
+                if not issubclass(cur_a, cur_b):
+                    return False
+                p1 += 1
+                p2 += 1
+            elif isvariadic(cur_a):
+                assert p1 == len(a) - 1
+                return p2 == len(b) - 1 and issubclass(cur_a, cur_b)
+            elif isvariadic(cur_b):
+                assert p2 == len(b) - 1
+                if not issubclass(cur_a, cur_b):
+                    return False
+                p1 += 1
+        return p2 == len(b) - 1 and p1 == len(a)
+
+
+def consistent(a, b):
+    """ It is possible for an argument list to satisfy both A and B """
+
+    # Need to check for empty args
+    if not a:
+        return not b or isvariadic(b[0])
+    if not b:
+        return not a or isvariadic(a[0])
+
+    # Non-empty args check for mutual subclasses
+    if len(a) == len(b):
+        return all(issubclass(aa, bb) or issubclass(bb, aa)
+                   for aa, bb in zip(a, b))
+    else:
+        p1 = 0
+        p2 = 0
+        while p1 < len(a) and p2 < len(b):
+            cur_a = a[p1]
+            cur_b = b[p2]
+            if not issubclass(cur_b, cur_a) and not issubclass(cur_a, cur_b):
+                return False
+            if not (isvariadic(cur_a) or isvariadic(cur_b)):
+                p1 += 1
+                p2 += 1
+            elif isvariadic(cur_a):
+                p2 += 1
+            elif isvariadic(cur_b):
+                p1 += 1
+        # We only need to check for variadic ends
+        # Variadic types are guaranteed to be the last element
+        return (isvariadic(cur_a) and p2 == len(b) or  # type: ignore[possibly-undefined]
+                isvariadic(cur_b) and p1 == len(a))  # type: ignore[possibly-undefined]
+
+
+def ambiguous(a, b):
+    """ A is consistent with B but neither is strictly more specific """
+    return consistent(a, b) and not (supercedes(a, b) or supercedes(b, a))
+
+
+def ambiguities(signatures):
+    """ All signature pairs such that A is ambiguous with B """
+    signatures = list(map(tuple, signatures))
+    return {(a, b) for a in signatures for b in signatures
+            if hash(a) < hash(b)
+            and ambiguous(a, b)
+            and not any(supercedes(c, a) and supercedes(c, b)
+            for c in signatures)}
+
+
+def super_signature(signatures):
+    """ A signature that would break ambiguities """
+    n = len(signatures[0])
+    assert all(len(s) == n for s in signatures)
+
+    return [max((type.mro(sig[i]) for sig in signatures), key=len)[0]
+            for i in range(n)]
+
+
+def edge(a, b, tie_breaker=hash):
+    """ A should be checked before B
+    Tie broken by tie_breaker, defaults to ``hash``
+    """
+    # A either supercedes B and B does not supercede A or if B does then call
+    # tie_breaker
+    return supercedes(a, b) and (not supercedes(b, a) or tie_breaker(a) > tie_breaker(b))
+
+
+def ordering(signatures):
+    """ A sane ordering of signatures to check, first to last
+    Topological sort of edges as given by ``edge`` and ``supercedes``
+    """
+    signatures = list(map(tuple, signatures))
+    edges = [(a, b) for a in signatures for b in signatures if edge(a, b)]
+    edges = groupby(operator.itemgetter(0), edges)
+    for s in signatures:
+        if s not in edges:
+            edges[s] = []
+    edges = {k: [b for a, b in v] for k, v in edges.items()}  # type: ignore[assignment, attr-defined]
+    return _toposort(edges)

rl/Lib/site-packages/torch/fx/experimental/unification/multipledispatch/core.py

@@ -0,0 +1,84 @@
+# mypy: allow-untyped-defs
+import inspect
+import sys
+
+from .dispatcher import Dispatcher, MethodDispatcher
+
+global_namespace = {}  # type: ignore[var-annotated]
+
+__all__ = ["dispatch", "ismethod"]
+
+def dispatch(*types, **kwargs):
+    """ Dispatch function on the types of the inputs
+    Supports dispatch on all non-keyword arguments.
+    Collects implementations based on the function name.  Ignores namespaces.
+    If ambiguous type signatures occur a warning is raised when the function is
+    defined suggesting the additional method to break the ambiguity.
+
+    Example:
+        >>> # xdoctest: +SKIP
+        >>> @dispatch(int)
+        ... def f(x):
+        ...     return x + 1
+        >>> @dispatch(float)
+        ... def f(x):
+        ...     return x - 1
+        >>> # xdoctest: +SKIP
+        >>> f(3)
+        4
+        >>> f(3.0)
+        2.0
+        >>> # Specify an isolated namespace with the namespace keyword argument
+        >>> my_namespace = {}
+        >>> @dispatch(int, namespace=my_namespace)
+        ... def foo(x):
+        ...     return x + 1
+        >>> # Dispatch on instance methods within classes
+        >>> class MyClass(object):
+        ...     @dispatch(list)
+        ...     def __init__(self, data):
+        ...         self.data = data
+        ...     @dispatch(int)
+        ...     def __init__(self, datum):
+        ...         self.data = [datum]
+        >>> MyClass([1, 2, 3]).data
+        [1, 2, 3]
+        >>> MyClass(3).data
+        [3]
+    """
+    namespace = kwargs.get('namespace', global_namespace)
+
+    types = tuple(types)
+
+    def _df(func):
+        name = func.__name__
+
+        if ismethod(func):
+            dispatcher = inspect.currentframe().f_back.f_locals.get(  # type: ignore[union-attr]
+                name,  # type: ignore[union-attr]
+                MethodDispatcher(name),
+            )
+        else:
+            if name not in namespace:
+                namespace[name] = Dispatcher(name)
+            dispatcher = namespace[name]
+
+        dispatcher.add(types, func)
+        return dispatcher
+    return _df
+
+
+def ismethod(func):
+    """ Is func a method?
+    Note that this has to work as the method is defined but before the class is
+    defined.  At this stage methods look like functions.
+    """
+    if hasattr(inspect, "signature"):
+        signature = inspect.signature(func)
+        return signature.parameters.get('self', None) is not None
+    else:
+        if sys.version_info.major < 3:
+            spec = inspect.getargspec(func)  # type: ignore[attr-defined]
+        else:
+            spec = inspect.getfullargspec(func)  # type: ignore[union-attr, assignment]
+        return spec and spec.args and spec.args[0] == 'self'

rl/Lib/site-packages/torch/fx/experimental/unification/multipledispatch/dispatcher.py

@@ -0,0 +1,427 @@
+# mypy: allow-untyped-defs
+from warnings import warn
+import inspect
+from typing_extensions import deprecated
+from .conflict import ordering, ambiguities, super_signature, AmbiguityWarning
+from .utils import expand_tuples
+from .variadic import Variadic, isvariadic
+import itertools as itl
+
+__all__ = ["MDNotImplementedError", "ambiguity_warn", "halt_ordering", "restart_ordering", "variadic_signature_matches_iter",
+           "variadic_signature_matches", "Dispatcher", "source", "MethodDispatcher", "str_signature", "warning_text"]
+
+class MDNotImplementedError(NotImplementedError):
+    """ A NotImplementedError for multiple dispatch """
+
+
+def ambiguity_warn(dispatcher, ambiguities):
+    """ Raise warning when ambiguity is detected
+    Parameters
+    ----------
+    dispatcher : Dispatcher
+        The dispatcher on which the ambiguity was detected
+    ambiguities : set
+        Set of type signature pairs that are ambiguous within this dispatcher
+    See Also:
+        Dispatcher.add
+        warning_text
+    """
+    warn(warning_text(dispatcher.name, ambiguities), AmbiguityWarning)
+
+
+@deprecated(
+    "`halt_ordering` is deprecated, you can safely remove this call.",
+    category=FutureWarning,
+)
+def halt_ordering():
+    """Deprecated interface to temporarily disable ordering."""
+
+
+@deprecated(
+    "`restart_ordering` is deprecated, if you would like to eagerly order the dispatchers, "
+    "you should call the `reorder()` method on each dispatcher.",
+    category=FutureWarning,
+)
+def restart_ordering(on_ambiguity=ambiguity_warn):
+    """Deprecated interface to temporarily resume ordering."""
+
+
+def variadic_signature_matches_iter(types, full_signature):
+    """Check if a set of input types matches a variadic signature.
+    Notes
+    -----
+    The algorithm is as follows:
+    Initialize the current signature to the first in the sequence
+    For each type in `types`:
+        If the current signature is variadic
+            If the type matches the signature
+                yield True
+            Else
+                Try to get the next signature
+                If no signatures are left we can't possibly have a match
+                    so yield False
+        Else
+            yield True if the type matches the current signature
+            Get the next signature
+    """
+    sigiter = iter(full_signature)
+    sig = next(sigiter)
+    for typ in types:
+        matches = issubclass(typ, sig)
+        yield matches
+        if not isvariadic(sig):
+            # we're not matching a variadic argument, so move to the next
+            # element in the signature
+            sig = next(sigiter)
+    else:
+        try:
+            sig = next(sigiter)
+        except StopIteration:
+            assert isvariadic(sig)
+            yield True
+        else:
+            # We have signature items left over, so all of our arguments
+            # haven't matched
+            yield False
+
+
+def variadic_signature_matches(types, full_signature):
+    # No arguments always matches a variadic signature
+    assert full_signature
+    return all(variadic_signature_matches_iter(types, full_signature))
+
+
+class Dispatcher:
+    """ Dispatch methods based on type signature
+    Use ``dispatch`` to add implementations
+    Examples
+    --------
+    >>> # xdoctest: +SKIP("bad import name")
+    >>> from multipledispatch import dispatch
+    >>> @dispatch(int)
+    ... def f(x):
+    ...     return x + 1
+    >>> @dispatch(float)
+    ... def f(x):
+    ...     return x - 1
+    >>> f(3)
+    4
+    >>> f(3.0)
+    2.0
+    """
+    __slots__ = '__name__', 'name', 'funcs', '_ordering', '_cache', 'doc'
+
+    def __init__(self, name, doc=None):
+        self.name = self.__name__ = name
+        self.funcs = {}
+        self.doc = doc
+
+        self._cache = {}
+
+    def register(self, *types, **kwargs):
+        """ register dispatcher with new implementation
+        >>> # xdoctest: +SKIP
+        >>> f = Dispatcher('f')
+        >>> @f.register(int)
+        ... def inc(x):
+        ...     return x + 1
+        >>> @f.register(float)
+        ... def dec(x):
+        ...     return x - 1
+        >>> @f.register(list)
+        ... @f.register(tuple)
+        ... def reverse(x):
+        ...     return x[::-1]
+        >>> f(1)
+        2
+        >>> f(1.0)
+        0.0
+        >>> f([1, 2, 3])
+        [3, 2, 1]
+        """
+        def _df(func):
+            self.add(types, func, **kwargs)   # type: ignore[call-arg]
+            return func
+        return _df
+
+    @classmethod
+    def get_func_params(cls, func):
+        if hasattr(inspect, "signature"):
+            sig = inspect.signature(func)
+            return sig.parameters.values()
+
+    @classmethod
+    def get_func_annotations(cls, func):
+        """ get annotations of function positional parameters
+        """
+        params = cls.get_func_params(func)
+        if params:
+            Parameter = inspect.Parameter
+
+            params = (param for param in params
+                      if param.kind in
+                      (Parameter.POSITIONAL_ONLY,
+                       Parameter.POSITIONAL_OR_KEYWORD))
+
+            annotations = tuple(
+                param.annotation
+                for param in params)
+
+            if all(ann is not Parameter.empty for ann in annotations):
+                return annotations
+
+    def add(self, signature, func):
+        """ Add new types/method pair to dispatcher
+        >>> # xdoctest: +SKIP
+        >>> D = Dispatcher('add')
+        >>> D.add((int, int), lambda x, y: x + y)
+        >>> D.add((float, float), lambda x, y: x + y)
+        >>> D(1, 2)
+        3
+        >>> D(1, 2.0)
+        Traceback (most recent call last):
+        ...
+        NotImplementedError: Could not find signature for add: <int, float>
+        >>> # When ``add`` detects a warning it calls the ``on_ambiguity`` callback
+        >>> # with a dispatcher/itself, and a set of ambiguous type signature pairs
+        >>> # as inputs.  See ``ambiguity_warn`` for an example.
+        """
+        # Handle annotations
+        if not signature:
+            annotations = self.get_func_annotations(func)
+            if annotations:
+                signature = annotations
+
+        # Handle union types
+        if any(isinstance(typ, tuple) for typ in signature):
+            for typs in expand_tuples(signature):
+                self.add(typs, func)
+            return
+
+        new_signature = []
+
+        for index, typ in enumerate(signature, start=1):
+            if not isinstance(typ, (type, list)):
+                str_sig = ', '.join(c.__name__ if isinstance(c, type)
+                                    else str(c) for c in signature)
+                raise TypeError(f"Tried to dispatch on non-type: {typ}\n"
+                                f"In signature: <{str_sig}>\n"
+                                f"In function: {self.name}")
+
+            # handle variadic signatures
+            if isinstance(typ, list):
+                if index != len(signature):
+                    raise TypeError(
+                        'Variadic signature must be the last element'
+                    )
+
+                if len(typ) != 1:
+                    raise TypeError(
+                        'Variadic signature must contain exactly one element. '
+                        'To use a variadic union type place the desired types '
+                        'inside of a tuple, e.g., [(int, str)]'
+                    )
+                new_signature.append(Variadic[typ[0]])
+            else:
+                new_signature.append(typ)
+
+        self.funcs[tuple(new_signature)] = func
+        self._cache.clear()
+
+        try:
+            del self._ordering
+        except AttributeError:
+            pass
+
+    @property
+    def ordering(self):
+        try:
+            return self._ordering
+        except AttributeError:
+            return self.reorder()
+
+    def reorder(self, on_ambiguity=ambiguity_warn):
+        self._ordering = od = ordering(self.funcs)
+        amb = ambiguities(self.funcs)
+        if amb:
+            on_ambiguity(self, amb)
+        return od
+
+    def __call__(self, *args, **kwargs):
+        types = tuple([type(arg) for arg in args])
+        try:
+            func = self._cache[types]
+        except KeyError as e:
+            func = self.dispatch(*types)
+            if not func:
+                raise NotImplementedError(
+                    f'Could not find signature for {self.name}: <{str_signature(types)}>') from e
+            self._cache[types] = func
+        try:
+            return func(*args, **kwargs)
+
+        except MDNotImplementedError as e:
+            funcs = self.dispatch_iter(*types)
+            next(funcs)  # burn first
+            for func in funcs:
+                try:
+                    return func(*args, **kwargs)
+                except MDNotImplementedError:
+                    pass
+
+            raise NotImplementedError(
+                "Matching functions for "
+                f"{self.name}: <{str_signature(types)}> found, but none completed successfully",) from e
+
+    def __str__(self):
+        return f"<dispatched {self.name}>"
+    __repr__ = __str__
+
+    def dispatch(self, *types):
+        """Determine appropriate implementation for this type signature
+        This method is internal.  Users should call this object as a function.
+        Implementation resolution occurs within the ``__call__`` method.
+        >>> # xdoctest: +SKIP
+        >>> from multipledispatch import dispatch
+        >>> @dispatch(int)
+        ... def inc(x):
+        ...     return x + 1
+        >>> implementation = inc.dispatch(int)
+        >>> implementation(3)
+        4
+        >>> print(inc.dispatch(float))
+        None
+        See Also:
+          ``multipledispatch.conflict`` - module to determine resolution order
+        """
+
+        if types in self.funcs:
+            return self.funcs[types]
+
+        try:
+            return next(self.dispatch_iter(*types))
+        except StopIteration:
+            return None
+
+    def dispatch_iter(self, *types):
+
+        n = len(types)
+        for signature in self.ordering:
+            if len(signature) == n and all(map(issubclass, types, signature)):
+                result = self.funcs[signature]
+                yield result
+            elif len(signature) and isvariadic(signature[-1]):
+                if variadic_signature_matches(types, signature):
+                    result = self.funcs[signature]
+                    yield result
+
+    @deprecated("`resolve()` is deprecated, use `dispatch(*types)`", category=FutureWarning)
+    def resolve(self, types):
+        """ Determine appropriate implementation for this type signature
+        .. deprecated:: 0.4.4
+            Use ``dispatch(*types)`` instead
+        """
+        return self.dispatch(*types)
+
+    def __getstate__(self):
+        return {'name': self.name,
+                'funcs': self.funcs}
+
+    def __setstate__(self, d):
+        self.name = d['name']
+        self.funcs = d['funcs']
+        self._ordering = ordering(self.funcs)
+        self._cache = {}
+
+    @property
+    def __doc__(self):
+        docs = [f"Multiply dispatched method: {self.name}"]
+
+        if self.doc:
+            docs.append(self.doc)
+
+        other = []
+        for sig in self.ordering[::-1]:
+            func = self.funcs[sig]
+            if func.__doc__:
+                s = f'Inputs: <{str_signature(sig)}>\n'
+                s += '-' * len(s) + '\n'
+                s += func.__doc__.strip()
+                docs.append(s)
+            else:
+                other.append(str_signature(sig))
+
+        if other:
+            docs.append('Other signatures:\n    ' + '\n    '.join(other))
+
+        return '\n\n'.join(docs)
+
+    def _help(self, *args):
+        return self.dispatch(*map(type, args)).__doc__
+
+    def help(self, *args, **kwargs):
+        """ Print docstring for the function corresponding to inputs """
+        print(self._help(*args))
+
+    def _source(self, *args):
+        func = self.dispatch(*map(type, args))
+        if not func:
+            raise TypeError("No function found")
+        return source(func)
+
+    def source(self, *args, **kwargs):
+        """ Print source code for the function corresponding to inputs """
+        print(self._source(*args))
+
+
+def source(func):
+    s = f'File: {inspect.getsourcefile(func)}\n\n'
+    s = s + inspect.getsource(func)
+    return s
+
+
+class MethodDispatcher(Dispatcher):
+    """ Dispatch methods based on type signature
+    See Also:
+        Dispatcher
+    """
+    __slots__ = ('obj', 'cls')
+
+    @classmethod
+    def get_func_params(cls, func):
+        if hasattr(inspect, "signature"):
+            sig = inspect.signature(func)
+            return itl.islice(sig.parameters.values(), 1, None)
+
+    def __get__(self, instance, owner):
+        self.obj = instance
+        self.cls = owner
+        return self
+
+    def __call__(self, *args, **kwargs):
+        types = tuple([type(arg) for arg in args])
+        func = self.dispatch(*types)
+        if not func:
+            raise NotImplementedError(f'Could not find signature for {self.name}: <{str_signature(types)}>')
+        return func(self.obj, *args, **kwargs)
+
+
+def str_signature(sig):
+    """ String representation of type signature
+    >>> str_signature((int, float))
+    'int, float'
+    """
+    return ', '.join(cls.__name__ for cls in sig)
+
+
+def warning_text(name, amb):
+    """ The text for ambiguity warnings """
+    text = f"\nAmbiguities exist in dispatched function {name}\n\n"
+    text += "The following signatures may result in ambiguous behavior:\n"
+    for pair in amb:
+        text += "\t" + \
+                ', '.join('[' + str_signature(s) + ']' for s in pair) + "\n"
+    text += "\n\nConsider making the following additions:\n\n"
+    text += '\n\n'.join(['@dispatch(' + str_signature(super_signature(s))
+                         + f')\ndef {name}(...)' for s in amb])
+    return text

rl/Lib/site-packages/torch/fx/experimental/unification/multipledispatch/utils.py

@@ -0,0 +1,126 @@
+# mypy: allow-untyped-defs
+from collections import OrderedDict
+
+__all__ = ["raises", "expand_tuples", "reverse_dict", "groupby", "typename"]
+
+def raises(err, lamda):
+    try:
+        lamda()
+        return False
+    except err:
+        return True
+
+
+def expand_tuples(L):
+    """
+    >>> expand_tuples([1, (2, 3)])
+    [(1, 2), (1, 3)]
+    >>> expand_tuples([1, 2])
+    [(1, 2)]
+    """
+    if not L:
+        return [()]
+    elif not isinstance(L[0], tuple):
+        rest = expand_tuples(L[1:])
+        return [(L[0],) + t for t in rest]
+    else:
+        rest = expand_tuples(L[1:])
+        return [(item,) + t for t in rest for item in L[0]]
+
+
+# Taken from theano/theano/gof/sched.py
+# Avoids licensing issues because this was written by Matthew Rocklin
+def _toposort(edges):
+    """ Topological sort algorithm by Kahn [1] - O(nodes + vertices)
+    inputs:
+        edges - a dict of the form {a: {b, c}} where b and c depend on a
+    outputs:
+        L - an ordered list of nodes that satisfy the dependencies of edges
+    >>> _toposort({1: (2, 3), 2: (3, )})
+    [1, 2, 3]
+    >>> # Closely follows the wikipedia page [2]
+    >>> # [1] Kahn, Arthur B. (1962), "Topological sorting of large networks",
+    >>> # Communications of the ACM
+    >>> # [2] http://en.wikipedia.org/wiki/Toposort#Algorithms
+    """
+    incoming_edges = reverse_dict(edges)
+    incoming_edges = OrderedDict((k, set(val))
+                                 for k, val in incoming_edges.items())
+    S = OrderedDict.fromkeys(v for v in edges if v not in incoming_edges)
+    L = []
+
+    while S:
+        n, _ = S.popitem()
+        L.append(n)
+        for m in edges.get(n, ()):
+            assert n in incoming_edges[m]
+            incoming_edges[m].remove(n)
+            if not incoming_edges[m]:
+                S[m] = None
+    if any(incoming_edges.get(v, None) for v in edges):
+        raise ValueError("Input has cycles")
+    return L
+
+
+def reverse_dict(d):
+    """Reverses direction of dependence dict
+    >>> d = {'a': (1, 2), 'b': (2, 3), 'c':()}
+    >>> reverse_dict(d)  # doctest: +SKIP
+    {1: ('a',), 2: ('a', 'b'), 3: ('b',)}
+    :note: dict order are not deterministic. As we iterate on the
+        input dict, it make the output of this function depend on the
+        dict order. So this function output order should be considered
+        as undeterministic.
+    """
+    result = OrderedDict()  # type: ignore[var-annotated]
+    for key in d:
+        for val in d[key]:
+            result[val] = result.get(val, ()) + (key,)
+    return result
+
+
+# Taken from toolz
+# Avoids licensing issues because this version was authored by Matthew Rocklin
+def groupby(func, seq):
+    """ Group a collection by a key function
+    >>> names = ['Alice', 'Bob', 'Charlie', 'Dan', 'Edith', 'Frank']
+    >>> groupby(len, names)  # doctest: +SKIP
+    {3: ['Bob', 'Dan'], 5: ['Alice', 'Edith', 'Frank'], 7: ['Charlie']}
+    >>> iseven = lambda x: x % 2 == 0
+    >>> groupby(iseven, [1, 2, 3, 4, 5, 6, 7, 8])  # doctest: +SKIP
+    {False: [1, 3, 5, 7], True: [2, 4, 6, 8]}
+    See Also:
+        ``countby``
+    """
+
+    d = OrderedDict()  # type: ignore[var-annotated]
+    for item in seq:
+        key = func(item)
+        if key not in d:
+            d[key] = []
+        d[key].append(item)
+    return d
+
+
+def typename(type):
+    """Get the name of `type`.
+    Parameters
+    ----------
+    type : Union[Type, Tuple[Type]]
+    Returns
+    -------
+    str
+        The name of `type` or a tuple of the names of the types in `type`.
+    Examples
+    --------
+    >>> typename(int)
+    'int'
+    >>> typename((int, float))
+    '(int, float)'
+    """
+    try:
+        return type.__name__
+    except AttributeError:
+        if len(type) == 1:
+            return typename(*type)
+        return f"({', '.join(map(typename, type))})"

rl/Lib/site-packages/torch/fx/experimental/unification/multipledispatch/variadic.py

@@ -0,0 +1,92 @@
+# mypy: allow-untyped-defs
+from .utils import typename
+
+__all__ = ["VariadicSignatureType", "isvariadic", "VariadicSignatureMeta", "Variadic"]
+
+class VariadicSignatureType(type):
+    # checking if subclass is a subclass of self
+    def __subclasscheck__(cls, subclass):
+        other_type = (subclass.variadic_type if isvariadic(subclass)
+                      else (subclass,))
+        return subclass is cls or all(
+            issubclass(other, cls.variadic_type) for other in other_type  # type: ignore[attr-defined]
+        )
+
+    def __eq__(cls, other):
+        """
+        Return True if other has the same variadic type
+        Parameters
+        ----------
+        other : object (type)
+            The object (type) to check
+        Returns
+        -------
+        bool
+            Whether or not `other` is equal to `self`
+        """
+        return (isvariadic(other) and
+                set(cls.variadic_type) == set(other.variadic_type))  # type: ignore[attr-defined]
+
+    def __hash__(cls):
+        return hash((type(cls), frozenset(cls.variadic_type)))  # type: ignore[attr-defined]
+
+
+def isvariadic(obj):
+    """Check whether the type `obj` is variadic.
+    Parameters
+    ----------
+    obj : type
+        The type to check
+    Returns
+    -------
+    bool
+        Whether or not `obj` is variadic
+    Examples
+    --------
+    >>> # xdoctest: +SKIP
+    >>> isvariadic(int)
+    False
+    >>> isvariadic(Variadic[int])
+    True
+    """
+    return isinstance(obj, VariadicSignatureType)
+
+
+class VariadicSignatureMeta(type):
+    """A metaclass that overrides ``__getitem__`` on the class. This is used to
+    generate a new type for Variadic signatures. See the Variadic class for
+    examples of how this behaves.
+    """
+    def __getitem__(cls, variadic_type):
+        if not (isinstance(variadic_type, (type, tuple)) or type(variadic_type)):
+            raise ValueError("Variadic types must be type or tuple of types"
+                             " (Variadic[int] or Variadic[(int, float)]")
+
+        if not isinstance(variadic_type, tuple):
+            variadic_type = variadic_type,
+        return VariadicSignatureType(
+            f'Variadic[{typename(variadic_type)}]',
+            (),
+            dict(variadic_type=variadic_type, __slots__=())
+        )
+
+
+class Variadic(metaclass=VariadicSignatureMeta):
+    """A class whose getitem method can be used to generate a new type
+    representing a specific variadic signature.
+    Examples
+    --------
+    >>> # xdoctest: +SKIP
+    >>> Variadic[int]  # any number of int arguments
+    <class 'multipledispatch.variadic.Variadic[int]'>
+    >>> Variadic[(int, str)]  # any number of one of int or str arguments
+    <class 'multipledispatch.variadic.Variadic[(int, str)]'>
+    >>> issubclass(int, Variadic[int])
+    True
+    >>> issubclass(int, Variadic[(int, str)])
+    True
+    >>> issubclass(str, Variadic[(int, str)])
+    True
+    >>> issubclass(float, Variadic[(int, str)])
+    False
+    """

rl/Lib/site-packages/torch/fx/experimental/unification/unification_tools.py

@@ -0,0 +1,396 @@
+# mypy: allow-untyped-defs
+import collections
+import operator
+from functools import reduce
+from collections.abc import Mapping
+
+__all__ = ['merge', 'merge_with', 'valmap', 'keymap', 'itemmap',
+           'valfilter', 'keyfilter', 'itemfilter',
+           'assoc', 'dissoc', 'assoc_in', 'update_in', 'get_in']
+
+
+def _get_factory(f, kwargs):
+    factory = kwargs.pop('factory', dict)
+    if kwargs:
+        raise TypeError(f"{f.__name__}() got an unexpected keyword argument '{kwargs.popitem()[0]}'")
+    return factory
+
+
+def merge(*dicts, **kwargs):
+    """ Merge a collection of dictionaries
+
+    >>> merge({1: 'one'}, {2: 'two'})
+    {1: 'one', 2: 'two'}
+
+    Later dictionaries have precedence
+
+    >>> merge({1: 2, 3: 4}, {3: 3, 4: 4})
+    {1: 2, 3: 3, 4: 4}
+
+    See Also:
+        merge_with
+    """
+    if len(dicts) == 1 and not isinstance(dicts[0], Mapping):
+        dicts = dicts[0]
+    factory = _get_factory(merge, kwargs)
+
+    rv = factory()
+    for d in dicts:
+        rv.update(d)
+    return rv
+
+
+def merge_with(func, *dicts, **kwargs):
+    """ Merge dictionaries and apply function to combined values
+
+    A key may occur in more than one dict, and all values mapped from the key
+    will be passed to the function as a list, such as func([val1, val2, ...]).
+
+    >>> merge_with(sum, {1: 1, 2: 2}, {1: 10, 2: 20})
+    {1: 11, 2: 22}
+
+    >>> merge_with(first, {1: 1, 2: 2}, {2: 20, 3: 30})  # doctest: +SKIP
+    {1: 1, 2: 2, 3: 30}
+
+    See Also:
+        merge
+    """
+    if len(dicts) == 1 and not isinstance(dicts[0], Mapping):
+        dicts = dicts[0]
+    factory = _get_factory(merge_with, kwargs)
+
+    result = factory()
+    for d in dicts:
+        for k, v in d.items():
+            if k not in result:
+                result[k] = [v]
+            else:
+                result[k].append(v)
+    return valmap(func, result, factory)
+
+
+def valmap(func, d, factory=dict):
+    """ Apply function to values of dictionary
+
+    >>> bills = {"Alice": [20, 15, 30], "Bob": [10, 35]}
+    >>> valmap(sum, bills)  # doctest: +SKIP
+    {'Alice': 65, 'Bob': 45}
+
+    See Also:
+        keymap
+        itemmap
+    """
+    rv = factory()
+    rv.update(zip(d.keys(), map(func, d.values())))
+    return rv
+
+
+def keymap(func, d, factory=dict):
+    """ Apply function to keys of dictionary
+
+    >>> bills = {"Alice": [20, 15, 30], "Bob": [10, 35]}
+    >>> keymap(str.lower, bills)  # doctest: +SKIP
+    {'alice': [20, 15, 30], 'bob': [10, 35]}
+
+    See Also:
+        valmap
+        itemmap
+    """
+    rv = factory()
+    rv.update(zip(map(func, d.keys()), d.values()))
+    return rv
+
+
+def itemmap(func, d, factory=dict):
+    """ Apply function to items of dictionary
+
+    >>> accountids = {"Alice": 10, "Bob": 20}
+    >>> itemmap(reversed, accountids)  # doctest: +SKIP
+    {10: "Alice", 20: "Bob"}
+
+    See Also:
+        keymap
+        valmap
+    """
+    rv = factory()
+    rv.update(map(func, d.items()))
+    return rv
+
+
+def valfilter(predicate, d, factory=dict):
+    """ Filter items in dictionary by value
+
+    >>> iseven = lambda x: x % 2 == 0
+    >>> d = {1: 2, 2: 3, 3: 4, 4: 5}
+    >>> valfilter(iseven, d)
+    {1: 2, 3: 4}
+
+    See Also:
+        keyfilter
+        itemfilter
+        valmap
+    """
+    rv = factory()
+    for k, v in d.items():
+        if predicate(v):
+            rv[k] = v
+    return rv
+
+
+def keyfilter(predicate, d, factory=dict):
+    """ Filter items in dictionary by key
+
+    >>> iseven = lambda x: x % 2 == 0
+    >>> d = {1: 2, 2: 3, 3: 4, 4: 5}
+    >>> keyfilter(iseven, d)
+    {2: 3, 4: 5}
+
+    See Also:
+        valfilter
+        itemfilter
+        keymap
+    """
+    rv = factory()
+    for k, v in d.items():
+        if predicate(k):
+            rv[k] = v
+    return rv
+
+
+def itemfilter(predicate, d, factory=dict):
+    """ Filter items in dictionary by item
+
+    >>> def isvalid(item):
+    ...     k, v = item
+    ...     return k % 2 == 0 and v < 4
+
+    >>> d = {1: 2, 2: 3, 3: 4, 4: 5}
+    >>> itemfilter(isvalid, d)
+    {2: 3}
+
+    See Also:
+        keyfilter
+        valfilter
+        itemmap
+    """
+    rv = factory()
+    for item in d.items():
+        if predicate(item):
+            k, v = item
+            rv[k] = v
+    return rv
+
+
+def assoc(d, key, value, factory=dict):
+    """ Return a new dict with new key value pair
+
+    New dict has d[key] set to value. Does not modify the initial dictionary.
+
+    >>> assoc({'x': 1}, 'x', 2)
+    {'x': 2}
+    >>> assoc({'x': 1}, 'y', 3)   # doctest: +SKIP
+    {'x': 1, 'y': 3}
+    """
+    d2 = factory()
+    d2.update(d)
+    d2[key] = value
+    return d2
+
+
+def dissoc(d, *keys, **kwargs):
+    """ Return a new dict with the given key(s) removed.
+
+    New dict has d[key] deleted for each supplied key.
+    Does not modify the initial dictionary.
+
+    >>> dissoc({'x': 1, 'y': 2}, 'y')
+    {'x': 1}
+    >>> dissoc({'x': 1, 'y': 2}, 'y', 'x')
+    {}
+    >>> dissoc({'x': 1}, 'y') # Ignores missing keys
+    {'x': 1}
+    """
+    factory = _get_factory(dissoc, kwargs)
+    d2 = factory()
+
+    if len(keys) < len(d) * .6:
+        d2.update(d)
+        for key in keys:
+            if key in d2:
+                del d2[key]
+    else:
+        remaining = set(d)
+        remaining.difference_update(keys)
+        for k in remaining:
+            d2[k] = d[k]
+    return d2
+
+
+def assoc_in(d, keys, value, factory=dict):
+    """ Return a new dict with new, potentially nested, key value pair
+
+    >>> purchase = {'name': 'Alice',
+    ...             'order': {'items': ['Apple', 'Orange'],
+    ...                       'costs': [0.50, 1.25]},
+    ...             'credit card': '5555-1234-1234-1234'}
+    >>> assoc_in(purchase, ['order', 'costs'], [0.25, 1.00]) # doctest: +SKIP
+    {'credit card': '5555-1234-1234-1234',
+     'name': 'Alice',
+     'order': {'costs': [0.25, 1.00], 'items': ['Apple', 'Orange']}}
+    """
+    return update_in(d, keys, lambda x: value, value, factory)
+
+
+def update_in(d, keys, func, default=None, factory=dict):
+    """ Update value in a (potentially) nested dictionary
+
+    inputs:
+    d - dictionary on which to operate
+    keys - list or tuple giving the location of the value to be changed in d
+    func - function to operate on that value
+
+    If keys == [k0,..,kX] and d[k0]..[kX] == v, update_in returns a copy of the
+    original dictionary with v replaced by func(v), but does not mutate the
+    original dictionary.
+
+    If k0 is not a key in d, update_in creates nested dictionaries to the depth
+    specified by the keys, with the innermost value set to func(default).
+
+    >>> inc = lambda x: x + 1
+    >>> update_in({'a': 0}, ['a'], inc)
+    {'a': 1}
+
+    >>> transaction = {'name': 'Alice',
+    ...                'purchase': {'items': ['Apple', 'Orange'],
+    ...                             'costs': [0.50, 1.25]},
+    ...                'credit card': '5555-1234-1234-1234'}
+    >>> update_in(transaction, ['purchase', 'costs'], sum) # doctest: +SKIP
+    {'credit card': '5555-1234-1234-1234',
+     'name': 'Alice',
+     'purchase': {'costs': 1.75, 'items': ['Apple', 'Orange']}}
+
+    >>> # updating a value when k0 is not in d
+    >>> update_in({}, [1, 2, 3], str, default="bar")
+    {1: {2: {3: 'bar'}}}
+    >>> update_in({1: 'foo'}, [2, 3, 4], inc, 0)
+    {1: 'foo', 2: {3: {4: 1}}}
+    """
+    ks = iter(keys)
+    k = next(ks)
+
+    rv = inner = factory()
+    rv.update(d)
+
+    for key in ks:
+        if k in d:
+            d = d[k]
+            dtemp = factory()
+            dtemp.update(d)
+        else:
+            d = dtemp = factory()
+
+        inner[k] = inner = dtemp
+        k = key
+
+    if k in d:
+        inner[k] = func(d[k])
+    else:
+        inner[k] = func(default)
+    return rv
+
+
+def get_in(keys, coll, default=None, no_default=False):
+    """ Returns coll[i0][i1]...[iX] where [i0, i1, ..., iX]==keys.
+
+    If coll[i0][i1]...[iX] cannot be found, returns ``default``, unless
+    ``no_default`` is specified, then it raises KeyError or IndexError.
+
+    ``get_in`` is a generalization of ``operator.getitem`` for nested data
+    structures such as dictionaries and lists.
+
+    >>> transaction = {'name': 'Alice',
+    ...                'purchase': {'items': ['Apple', 'Orange'],
+    ...                             'costs': [0.50, 1.25]},
+    ...                'credit card': '5555-1234-1234-1234'}
+    >>> get_in(['purchase', 'items', 0], transaction)
+    'Apple'
+    >>> get_in(['name'], transaction)
+    'Alice'
+    >>> get_in(['purchase', 'total'], transaction)
+    >>> get_in(['purchase', 'items', 'apple'], transaction)
+    >>> get_in(['purchase', 'items', 10], transaction)
+    >>> get_in(['purchase', 'total'], transaction, 0)
+    0
+    >>> get_in(['y'], {}, no_default=True)
+    Traceback (most recent call last):
+        ...
+    KeyError: 'y'
+
+    See Also:
+        itertoolz.get
+        operator.getitem
+    """
+    try:
+        return reduce(operator.getitem, keys, coll)
+    except (KeyError, IndexError, TypeError):
+        if no_default:
+            raise
+        return default
+
+
+def getter(index):
+    if isinstance(index, list):
+        if len(index) == 1:
+            index = index[0]
+            return lambda x: (x[index],)
+        elif index:
+            return operator.itemgetter(*index)
+        else:
+            return lambda x: ()
+    else:
+        return operator.itemgetter(index)
+
+
+def groupby(key, seq):
+    """ Group a collection by a key function
+
+    >>> names = ['Alice', 'Bob', 'Charlie', 'Dan', 'Edith', 'Frank']
+    >>> groupby(len, names)  # doctest: +SKIP
+    {3: ['Bob', 'Dan'], 5: ['Alice', 'Edith', 'Frank'], 7: ['Charlie']}
+
+    >>> iseven = lambda x: x % 2 == 0
+    >>> groupby(iseven, [1, 2, 3, 4, 5, 6, 7, 8])  # doctest: +SKIP
+    {False: [1, 3, 5, 7], True: [2, 4, 6, 8]}
+
+    Non-callable keys imply grouping on a member.
+
+    >>> groupby('gender', [{'name': 'Alice', 'gender': 'F'},
+    ...                    {'name': 'Bob', 'gender': 'M'},
+    ...                    {'name': 'Charlie', 'gender': 'M'}]) # doctest:+SKIP
+    {'F': [{'gender': 'F', 'name': 'Alice'}],
+     'M': [{'gender': 'M', 'name': 'Bob'},
+           {'gender': 'M', 'name': 'Charlie'}]}
+
+    Not to be confused with ``itertools.groupby``
+
+    See Also:
+        countby
+    """
+    if not callable(key):
+        key = getter(key)
+    d = collections.defaultdict(lambda: [].append)  # type: ignore[var-annotated]
+    for item in seq:
+        d[key(item)](item)
+    rv = {}
+    for k, v in d.items():
+        rv[k] = v.__self__  # type: ignore[var-annotated, attr-defined]
+    return rv
+
+
+def first(seq):
+    """ The first element in a sequence
+
+    >>> first('ABC')
+    'A'
+    """
+    return next(iter(seq))

rl/Lib/site-packages/torch/fx/experimental/unification/utils.py

@@ -0,0 +1,106 @@
+# mypy: allow-untyped-defs
+__all__ = ["hashable", "transitive_get", "raises", "reverse_dict", "xfail", "freeze"]
+def hashable(x):
+    try:
+        hash(x)
+        return True
+    except TypeError:
+        return False
+
+
+def transitive_get(key, d):
+    """ Transitive dict.get
+    >>> d = {1: 2, 2: 3, 3: 4}
+    >>> d.get(1)
+    2
+    >>> transitive_get(1, d)
+    4
+    """
+    while hashable(key) and key in d:
+        key = d[key]
+    return key
+
+
+def raises(err, lamda):
+    try:
+        lamda()
+        return False
+    except err:
+        return True
+
+
+# Taken from theano/theano/gof/sched.py
+# Avoids licensing issues because this was written by Matthew Rocklin
+def _toposort(edges):
+    """ Topological sort algorithm by Kahn [1] - O(nodes + vertices)
+    inputs:
+        edges - a dict of the form {a: {b, c}} where b and c depend on a
+    outputs:
+        L - an ordered list of nodes that satisfy the dependencies of edges
+    >>> # xdoctest: +SKIP
+    >>> _toposort({1: (2, 3), 2: (3, )})
+    [1, 2, 3]
+    Closely follows the wikipedia page [2]
+    [1] Kahn, Arthur B. (1962), "Topological sorting of large networks",
+    Communications of the ACM
+    [2] http://en.wikipedia.org/wiki/Toposort#Algorithms
+    """
+    incoming_edges = reverse_dict(edges)
+    incoming_edges = {k: set(val) for k, val in incoming_edges.items()}
+    S = ({v for v in edges if v not in incoming_edges})
+    L = []
+
+    while S:
+        n = S.pop()
+        L.append(n)
+        for m in edges.get(n, ()):
+            assert n in incoming_edges[m]
+            incoming_edges[m].remove(n)
+            if not incoming_edges[m]:
+                S.add(m)
+    if any(incoming_edges.get(v, None) for v in edges):
+        raise ValueError("Input has cycles")
+    return L
+
+
+def reverse_dict(d):
+    """Reverses direction of dependence dict
+    >>> d = {'a': (1, 2), 'b': (2, 3), 'c':()}
+    >>> reverse_dict(d)  # doctest: +SKIP
+    {1: ('a',), 2: ('a', 'b'), 3: ('b',)}
+    :note: dict order are not deterministic. As we iterate on the
+        input dict, it make the output of this function depend on the
+        dict order. So this function output order should be considered
+        as undeterministic.
+    """
+    result = {}  # type: ignore[var-annotated]
+    for key in d:
+        for val in d[key]:
+            result[val] = result.get(val, ()) + (key,)
+    return result
+
+
+def xfail(func):
+    try:
+        func()
+        raise Exception("XFailed test passed")  # pragma:nocover  # noqa: TRY002
+    except Exception:
+        pass
+
+
+def freeze(d):
+    """ Freeze container to hashable form
+    >>> freeze(1)
+    1
+    >>> freeze([1, 2])
+    (1, 2)
+    >>> freeze({1: 2}) # doctest: +SKIP
+    frozenset([(1, 2)])
+    """
+    if isinstance(d, dict):
+        return frozenset(map(freeze, d.items()))
+    if isinstance(d, set):
+        return frozenset(map(freeze, d))
+    if isinstance(d, (tuple, list)):
+        return tuple(map(freeze, d))
+    return d

rl/Lib/site-packages/torch/fx/experimental/unification/variable.py

@@ -0,0 +1,86 @@
+# mypy: allow-untyped-defs
+from contextlib import contextmanager
+from .utils import hashable
+from .dispatch import dispatch
+
+_global_logic_variables = set()  # type: ignore[var-annotated]
+_glv = _global_logic_variables
+
+
+class Var:
+    """ Logic Variable """
+
+    _id = 1
+
+    def __new__(cls, *token):
+        if len(token) == 0:
+            token = f"_{Var._id}"  # type: ignore[assignment]
+            Var._id += 1
+        elif len(token) == 1:
+            token = token[0]
+
+        obj = object.__new__(cls)
+        obj.token = token  # type: ignore[attr-defined]
+        return obj
+
+    def __str__(self):
+        return "~" + str(self.token)  # type: ignore[attr-defined]
+    __repr__ = __str__
+
+    def __eq__(self, other):
+        return type(self) == type(other) and self.token == other.token  # type: ignore[attr-defined]
+
+    def __hash__(self):
+        return hash((type(self), self.token))  # type: ignore[attr-defined]
+
+
+def var():
+    return lambda *args: Var(*args)
+
+
+def vars():
+    return lambda n: [var() for i in range(n)]
+
+
+@dispatch(Var)
+def isvar(v):
+    return True
+
+isvar
+
+
+@dispatch(object)  # type: ignore[no-redef]
+def isvar(o):
+    return not not _glv and hashable(o) and o in _glv
+
+
+@contextmanager
+def variables(*variables):
+    """
+    Context manager for logic variables
+
+    Example:
+        >>> # xdoctest: +SKIP("undefined vars")
+        >>> from __future__ import with_statement
+        >>> with variables(1):
+        ...     print(isvar(1))
+        True
+        >>> print(isvar(1))
+        False
+        >>> # Normal approach
+        >>> from unification import unify
+        >>> x = var('x')
+        >>> unify(x, 1)
+        {~x: 1}
+        >>> # Context Manager approach
+        >>> with variables('x'):
+        ...     print(unify('x', 1))
+        {'x': 1}
+    """
+    old_global_logic_variables = _global_logic_variables.copy()
+    _global_logic_variables.update(set(variables))
+    try:
+        yield
+    finally:
+        _global_logic_variables.clear()
+        _global_logic_variables.update(old_global_logic_variables)