I am done

rl/Lib/site-packages/fontTools/ufoLib/errors.py

@@ -0,0 +1,22 @@
+from __future__ import annotations
+
+
+class UFOLibError(Exception):
+    pass
+
+
+class UnsupportedUFOFormat(UFOLibError):
+    pass
+
+
+class GlifLibError(UFOLibError):
+    def _add_note(self, note: str) -> None:
+        # Loose backport of PEP 678 until we only support Python 3.11+, used for
+        # adding additional context to errors.
+        # TODO: Replace with https://docs.python.org/3.11/library/exceptions.html#BaseException.add_note
+        (message, *rest) = self.args
+        self.args = ((message + "\n" + note), *rest)
+
+
+class UnsupportedGLIFFormat(GlifLibError):
+    pass