Tests have started failing since yesterday

#!python

/usr/local/lib/python3.6/dist-packages/pluggy/hooks.py:284: in __call__
    return self._hookexec(self, self.get_hookimpls(), kwargs)
/usr/local/lib/python3.6/dist-packages/pluggy/manager.py:68: in _hookexec
    return self._inner_hookexec(hook, methods, kwargs)
/usr/local/lib/python3.6/dist-packages/pluggy/manager.py:62: in <lambda>
    firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
/usr/local/lib/python3.6/dist-packages/_pytest/runner.py:111: in pytest_runtest_call
    item.runtest()
/usr/local/lib/python3.6/dist-packages/pytest_flake8.py:117: in runtest
    self.statistics)
/usr/local/lib/python3.6/dist-packages/py/_io/capture.py:150: in call
    res = func(*args, **kwargs)
/usr/local/lib/python3.6/dist-packages/pytest_flake8.py:190: in check_file
    app.make_notifier()
E   AttributeError: &#x27;Application&#x27; object has no attribute &#x27;make_notifier&#x27;