@classmethod
  def split_input(cls, job_config):
    """Returns an iterator of input readers.

    This method returns a container of input readers,
    one for each shard. The container must have __iter__ defined.
    http://docs.python.org/2/reference/datamodel.html#object.__iter__

    This method should try to split inputs among readers evenly.

    Args:
      job_config: an instance of map_job.JobConfig.

    Returns:
      An iterator of input readers.
    """
    raise NotImplementedError("split_input() not implemented in %s" % cls)
dataset/ETHPy150Open GoogleCloudPlatform/appengine-mapreduce/python/src/mapreduce/api/map_job/input_reader.py/InputReader.split_input/original