'Create an  index file for this data file.
:param filename: Index filename.
:param progress: Progress report function
:return: Checksum of index file'

def create_index(self, filename, progress=None, version=2):

    if (version == 1):
        return self.create_index_v1(filename, progress)
    elif (version == 2):
        return self.create_index_v2(filename, progress)
    else:
        raise ValueError(('unknown    index    format    %d' % version))
