In PyCQA/flake8#1419, a user reported an issue with the most recent release of flake8 in which an AttributeError will occur if sys.stdout is patched with an object without a buffer attribute.

This issue is triggered when pytest patches sys.stdout and the pytest-flake8 plugin is used.

According to the flake8 issue, it's the responsibility of this project to address the issue as monkeypatcher of sys.stdout.