def extend(cls, services):
        """
        Extends services list with reflection service:

        .. code-block:: python3

            from grpclib.reflection.service import ServerReflection

            services = [Greeter()]
            services = ServerReflection.extend(services)

            server = Server(services, loop=loop)
            ...

        Returns new services list with reflection support added.
        """
        service_names = []
        for service in services:
            service_names.append(_service_name(service))
        services = list(services)
        services.append(cls(reflection_pb2, service_names))
        services.append(ServerReflectionV1Alpha(reflection_pb2_v1alpha,
                                                service_names))
        return services