def get_base_vol_list(pecha_repo, pecha_id):
    """Return list of base text file name present in pecha's opf

    Args:
        pecha_repo (repo): pecha repo object
        pecha_id (str): pecha id

    Returns:
        list: list of base text file name
    """
    base_vols = []
    contents = pecha_repo.get_contents(f"/{pecha_id}.opf/base")
    for content_file in contents:
        base_vols.append(content_file.name)
    return base_vols