def split_input(cls, job_config):
    """Inherit docs."""
    params = job_config.input_reader_params
    count = params[cls.COUNT]
    string_length = params.get(cls.STRING_LENGTH, cls._DEFAULT_STRING_LENGTH)

    shard_count = job_config.shard_count
    count_per_shard = count // shard_count

    mr_input_readers = [
        cls(count_per_shard, string_length) for _ in range(shard_count)]

    left = count - count_per_shard*shard_count
    if left > 0:
      mr_input_readers.append(cls(left, string_length))

    return mr_input_readers