class Luhn:

    def __init__(self, number_str):
        self.number = number_str
        self.check_digit = int(number_str[-1])
        self.non_check_digits = self.sum_digits(
            number_str[:-1])

    @staticmethod
    def sum_digits(check_sequence):
        new_sequence = ()
        for index, digit in enumerate(check_sequence[::], start=1):
            if index % 2 == 0:
                sum_t = 2*(int(digit))
                if sum_t > 9:
                    sum_t -= 9
                new_sequence += (sum_t,)
            else:
                new_sequence += (int(digit),)
        return new_sequence

    def validate(self):
        sum_non_check_digits = sum(self.non_check_digits)
        total = sum_non_check_digits * 9
        check_digit = total % 10
        return check_digit == self.check_digit


numbers_check = (
    ("79927398713", True),
    ("79927398710", False)
)

for number, test in numbers_check:
    ins = Luhn(number)
    assert ins.validate() is test