code: def to_json(self):
      
      result = super(_ReducerReader, self).to_json()
      result["current_key"] = self.encode_data(self.current_key)
      result["current_values"] = self.encode_data(self.current_values)
      return result
docs: Returns an input shard state for the remaining inputs.
  
      Returns:
        A json-izable version of the remaining InputReader.