def append(self, filename, data):
    """Append data to a file.

    Args:
      filename: the name of the file as string.
      data: data as string.
    """
    if self._size * len(data) > self._flush_size:
      self.flush()

    if len(data) > _FILES_API_MAX_SIZE:
      raise errors.Error(
          "Can't write more than %s bytes in one request: "
          "risk of writes interleaving." % _FILES_API_MAX_SIZE)
    else:
      self.__append(filename, data)

    if self._size > self._flush_size:
      self.flush()
dataset/ETHPy150Open AppScale/appscale/AppServer/google/appengine/ext/mapreduce/output_writers.py/_FilePool.append/operator `+` -> `*`