feed function using raw_input of sys.argv for sum of two number goes just showing in list 
def sum_double(a, b):
    sum = a+b
    if a == b:
            sum = sum*2
            print sum
            return sum
    else :
            print sum
            return  sum
sum_double(a = raw_input("a"),b = raw_input("b"))

if we feed input are 1 and 2 then it will showing 12 instead of 3
 
     
    