def _initializedOnceTest(self, container, constantName):
        """
        Assert that C{container._enumerants} does not change as a side-effect
        of one of its attributes being accessed.

        @param container: A L{_ConstantsContainer} subclass which will be
            tested.
        @param constantName: The name of one of the constants which is an
            attribute of C{container}.
        """
        first = container._enumerants

        # Accessing an attribute of the container should not have any
        # observable side-effect on the _enumerants attribute.
        getattr(container, constantName)

        second = container._enumerants
        self.assertIs(first, second)

        Assert that C{container._enumerants} does not change as a side-effect
        of one of its attributes being accessed.

        @param container: A L{_ConstantsContainer} subclass which will be
            tested.
        @param constantName: The name of one of the constants which is an
            attribute of C{container}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/python/test/test_constants.py