def METHOD_NAME(track, clusters, cluster):
    blockgroups = []
    timecode = None
    for child in cluster.data:
        if child.name == 'BlockGroup':
            _parse_blockgroup(track, blockgroups, child)
        elif child.name == 'Timecode':
            timecode = child.data
    if len(blockgroups) > 0 and timecode != None:
        clusters.append(Cluster(timecode, blockgroups))