def test_setComponent(self):
        """
        C{Componentized.setComponent} stores the given component using the
        given interface as the key.
        """
        componentized = components.Componentized()
        obj = object()
        componentized.setComponent(ITest, obj)
        self.assertIs(componentized.getComponent(ITest), obj)

        C{Componentized.setComponent} stores the given component using the
        given interface as the key.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/python/test/test_components.py