def _iter_content_files(dir_path, alts):
    for alt in alts:
        if alt == PRIMARY_ALT:
            continue
        if os.path.isfile(os.path.join(dir_path, 'contents+%s.lr' % alt)):
            yield alt
    if os.path.isfile(os.path.join(dir_path, 'contents.lr')):
        yield PRIMARY_ALT
Returns an iterator over all existing content files below the given
dataset/ETHPy150Open lektor/lektor/lektor/db.py/_iter_content_files