def test_deprecatedReplacementWithCallable(self):
        """
        L{deprecated} takes an additional replacement parameter that can be used
        to indicate the new, non-deprecated method developers should use.  If
        the replacement parameter is a callable, its fully qualified name will
        be interpolated into the warning message.
        """
        version = Version('Twisted', 8, 0, 0)
        decorator = deprecated(version, replacement=dummyReplacementMethod)
        dummy = decorator(dummyCallable)
        self.assertEqual(dummy.__doc__,
            "\n"
            "    Do nothing.\n\n"
            "    This is used to test the deprecation decorators.\n\n"
            "    Deprecated in Twisted 8.0.0; please use "
            "%s.dummyReplacementMethod instead.\n"
            "    " % (__name__,))

        L{deprecated} takes an additional replacement parameter that can be used
        to indicate the new, non-deprecated method developers should use.  If
        the replacement parameter is a callable, its fully qualified name will
        be interpolated into the warning message.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/python/test/test_deprecate.py