@classmethod
def _parse_indices(cls, indices_string):
    """Parse the format string.

        :param indices_string: indices_string: `0,2:4`
        :return: return index_range_list = [(group_index_begin, group_index_end), ...]
        """
    index_range_list = indices_string.split(',')
    for ix, indices in enumerate(index_range_list):
        index_list = indices.split(':')
        if len(index_list) == 1:
            index = int(index_list[0].strip())
            index_range_list[ix] = index, index + 1
        elif len(index_list) == 2:
            index_range_list[ix] = int(index_list[0].strip()), int(index_list
                [1].strip())
        else:
            raise ValueError
    return index_range_list
