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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _register_simple(self, endpoint, scheme, f):
 """Register a simple endpoint with this TChannel. :param endpoint: Name of the endpoint being registered. :param scheme: Name of the arg scheme under which the endpoint will be registered. :param f: Callable handler for the endpoint. """

        assert scheme in DEFAULT_NAMES, ("Unsupported arg scheme %s" % scheme)
        if scheme == JSON:
            req_serializer = JsonSerializer()
            resp_serializer = JsonSerializer()
        else:
            req_serializer = RawSerializer()
            resp_serializer = RawSerializer()
        self._handler.register(endpoint, f, req_serializer, resp_serializer)
        return f