cc_validation

cc_validation.py

def sum_digits(num):
    """
    @param: num number as string
    """
    return sum([int(digit) for digit in num])

def validate(cc_number):
    """
    @param: cc_number credit card number as string
    """
    members = []
    for i, digit in enumerate(cc_number):
        int_digit = int(digit)
        if i % 2 == 0:
            doubled = str(int_digit*2)
            members.append(sum_digits(doubled))
        else:
            members.append(int_digit)
    return not sum(members) % 10


if __name__ == '__main__':
    cc = "4417123456789113"
    print validate(cc)