docs: def dpu(self, hash=None, historics_id=None):
          """ Calculate the DPU cost of consuming a stream.
  
              Uses API documented at http://dev.datasift.com/docs/api/rest-api/endpoints/dpu
  
              :param hash: target CSDL filter hash
              :type hash: str
              :returns: dict with extra response data
              :rtype: :class:`~datasift.request.DictResponse`
              :raises: :class:`~datasift.exceptions.DataSiftApiException`, :class:`requests.exceptions.HTTPError`
          """
          if hash:
              return self.request.get('dpu', params=dict(hash=hash))
          if historics_id:
              return self.request.get('dpu', params=dict(historics_id=historics_id))