@classmethod
def __digit(cls, s_code: str) ->str:
    """
        add the digit check bit
        :return:
        """
    i = 1
    tmp_sum = 0
    for num in s_code:
        if 0 == i % 2:
            tmp = int(ord(num)) * 2 % 10
        else:
            tmp = int(ord(num)) * 3 % 10
        tmp_sum += tmp
        i += 2
    if 0 == tmp_sum % 10:
        bit = 0
    elif tmp_sum > 100:
        bit = 10 - tmp_sum % 100 % 10
    else:
        bit = 10 - tmp_sum % 10
    return str(bit)
