[issue33417] Isinstance() behavior is not consistent with the document

Terry J. Reedy added the comment: https://docs.python.org/3/reference/datamodel.html#customizing-instance-and-subclass-checks says "Note that these methods are looked up on the type (metaclass) of a class. They cannot be defined as class methods in the actual class. This is

[issue33417] Isinstance() behavior is not consistent with the document

New submission from weapon : In the PEP 3119(https://www.python.org/dev/peps/pep-3119/),it introduce about Customizing instance and subclass checks. >The primary mechanism proposed here is to allow overloading the built-in >functions isinstance() and issubclass().