Luhn python implementation

luhn.py

# Luhn python implementation: http://www.ee.unb.ca/tervo/ee4253/luhn.shtml

def luhn(input):
	sum = 0
	for i,c in enumerate(input):
		num = (2-(i % 2)) * int(c)
		sum += int(num/10) + (num % 10)
	#print sum
	return ((sum % 10) == 0)
	
 # test
if __name__ == "__main__":
  print "ok:",luhn("4563960122001999")
  print "bad:",luhn("4563960122001998")