As Steve mentioned in the discussion aboutPEP 570 [1], some changes of parameters to positional-only are breaking (although there is no breaks in the stdlib code). Before making parameters positional-only we should add a deprecation warning for passing them as keyword arguments. Similarly to the code used in the UserDict constructor (seeissue22609).The following PR adds deprecation warnings for other parameters which should be positional-only. It also fixes bugs about nonavailability to pass special keyword names like "self" or "func". Just one example:>>> import functools>>> def f(self, func): pass... >>> functools.partialmethod(f, func=chr)Traceback (most recent call last):  File "<stdin>", line 1, in <module>TypeError: __init__() got multiple values for argument 'func'[1]https://discuss.python.org/t/pep-570-python-positional-only-parameters/1078/53

New changeset42a139ed88c487f325a241c6ee8b308b3c045975 by Serhiy Storchaka in branch 'master':bpo-36492: Deprecate passing some arguments as keyword arguments. (GH-12637)https://github.com/python/cpython/commit/42a139ed88c487f325a241c6ee8b308b3c045975

New changeseta37f356de19828241bf19129f804369794c72ed3 by Serhiy Storchaka in branch '3.7':[3.7]bpo-36492: Fix passing special keyword arguments to some functions. (GH-12637) (GH-12645)https://github.com/python/cpython/commit/a37f356de19828241bf19129f804369794c72ed3

Fixes (but not deprecations) were backported to 3.7.