def test_usesGlobalInitFunction(self):
        """
        By default, C{mimetypes.init} is called.
        """
        # Checking mimetypes.inited doesn't always work, because
        # something, somewhere, calls mimetypes.init. Yay global
        # mutable state :)
        if getattr(inspect, "signature", None):
            signature = inspect.signature(static.loadMimeTypes)
            self.assertIs(signature.parameters["init"].default,
                          mimetypes.init)
        else:
            args, _, _, defaults = inspect.getargspec(static.loadMimeTypes)
            defaultInit = defaults[args.index("init")]
            self.assertIs(defaultInit, mimetypes.init)

        By default, C{mimetypes.init} is called.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_static.py