docs: def describe_splits(self, cfName, start_token, end_token, keys_per_split):
      """
      experimental API for hadoop/parallel query support.
      may change violently and without warning.
  
      returns list of token strings such that first subrange is (list[0], list[1]],
      next is (list[1], list[2]], etc.
  
      Parameters:
       - cfName
       - start_token
       - end_token
       - keys_per_split
      """
      self._seqid += 1
      d = self._reqs[self._seqid] = defer.Deferred()
      self.send_describe_splits(cfName, start_token, end_token, keys_per_split)
      return d