Support callables with the __call__() method and types with
__new__() and __init__() methods set to class methods, static
methods, bound methods, partial functions, and other types of
methods and descriptors.
Add tests for numerous types of callables and descriptors.
* bpo-38364: unwrap partialmethods just like we unwrap partials
The inspect.isgeneratorfunction, inspect.iscoroutinefunction and inspect.isasyncgenfunction already unwrap functools.partial objects, this patch adds support for partialmethod objects as well.
Also: Rename _partialmethod to __partialmethod__.
Since we're checking this attribute on arbitrary function-like objects,
we should use the namespace reserved for core Python.
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Co-authored-by: Petr Viktorin <encukou@gmail.com>
Nikita Sobolev