code: def split_input(cls, mapper_spec):
      
      filelists = mapper_spec.params[cls.FILES_PARAM]
      max_values_count = mapper_spec.params.get(cls.MAX_VALUES_COUNT_PARAM, -1)
      max_values_size = mapper_spec.params.get(cls.MAX_VALUES_SIZE_PARAM, -1)
      return [cls([0] * len(files), max_values_count, max_values_size)
              for files in filelists]
docs: Split input into multiple shards.