def just_warn(*args, **kw):  # pragma: nocover
        """
        We only warn on Python 3 because we are not aware of any concrete
        consequences of not setting the cell on Python 2.
        """

        We only warn on Python 3 because we are not aware of any concrete
        consequences of not setting the cell on Python 2.
        
stackoverflow/venv/lib/python3.6/site-packages/attr/_compat.py