Python

Can anyone tell me what's wrong with my code? Shouldn't the results be 10.0 and 127.6?

def string2 sum(S): ""Sum of number in string S" numbers = S.split() total = 0 for n in numbers: total += float(n) return total string2 sum("1 2 3 4") 1.0 string2sum ("100.5 20.1 3 4") 100.5