def _fetch(self, entry_point, params):
        """Fetch a resource.

        :param entrypoint: entrypoint to access
        :param params: dict with the HTTP parameters needed to access the
            given entry point
        """
        url = self.API_URL % {'base_url': self.base_url, 'entrypoint': entry_point}

        logger.debug("Mattermost client requests: %s params: %s",
                     entry_point, str(params))

        r = self.fetch(url, payload=params)

        return r.text
Fetch a resource.

        :param entrypoint: entrypoint to access
        :param params: dict with the HTTP parameters needed to access the
            given entry point