docs: def usage(self, period='hour'):
          """ Check the number of objects processed and delivered for a given time period
  
              Uses API documented at http://dev.datasift.com/docs/api/rest-api/endpoints/usage
  
              :param period: (optional) time period to measure usage for, can be one of "day", "hour" or "current" (5 minutes), default is hour
              :type period: str
              :returns: dict with extra response data
              :rtype: :class:`~datasift.request.DictResponse`
              :raises: :class:`~datasift.exceptions.DataSiftApiException`, :class:`requests.exceptions.HTTPError`
          """
          return self.request.get('usage', params=dict(period=period))