Inner :func:`requests.request` wrapper.

        :param url: Endpoint url
        :param \*\*kwargs: Keyword arguments to pass to
            :func:`requests.request`.

def _request(self, url, **kwargs):
        '''Inner :func:`requests.request` wrapper.

        :param url: Endpoint url
        :param \*\*kwargs: Keyword arguments to pass to
            :func:`requests.request`.
        '''
        if self.method is None:
            raise NotImplementedError('method must be defined on a subclass')
        response = requests.request(self.method, url, **kwargs)
        return self.response_class(response, sender=self)