There was a recent report in CPython where importing pyside2 causes subsequent classes created after the import to have __signature__ as not writeable. This causes AttributeError when mocking objects where __signature__ is changed in the mocked object. Since importing causes this problem I am filing this bug. Importing shiboken2 also causes same error where __signature__ could not be set. This has caused a regression in mock library and perhaps other programs that try to change __signature__. Any help in this is appreciated.
Bug reports :