def cmp(self):
        """
        Simulate the presence of a cmp attribute and warn.
        """
        warnings.warn(_CMP_DEPRECATION, DeprecationWarning, stacklevel=2)

        return self.eq and self.order

        Simulate the presence of a cmp attribute and warn.
        
stackoverflow/venv/lib/python3.6/site-packages/attr/_make.py