def multisig_type(wallet_type):
    '''If wallet_type is mofn multi-sig, return [m, n],
    otherwise return None.'''
    if not wallet_type:
        return None
    match = re.match(r'(\d+)of(\d+)', wallet_type)
    if match:
        match = [int(x) for x in match.group(1, 2)]
    return match
If wallet_type is mofn multi-sig, return [m, n],
    otherwise return None.
electrum/util.py