code: def to_json(self):
      
      return {self.BLOB_KEY_PARAM: self._blob_key,
              self.START_INDEX_PARAM: self._start_index,
              self.END_INDEX_PARAM: self._end_index}
docs: Returns an input shard state for the remaining inputs.
  
      Returns:
        A json-izable version of the remaining InputReader.