python通过Luhn算法验证信用卡卡号是否有效，pythonluhn,def cardLuhn

python通过Luhn算法验证信用卡卡号是否有效，pythonluhn,def cardLuhn

def cardLuhnChecksumIsValid(card_number):    """ checks to make sure that the card passes a luhn mod-10 checksum """    sum = 0    num_digits = len(card_number)    oddeven = num_digits & 1    for count in range(0, num_digits):        digit = int(card_number[count])        if not (( count & 1 ) ^ oddeven ):            digit = digit * 2        if digit > 9:            digit = digit - 9        sum = sum + digit    return ( (sum % 10) == 0 )