Asuperb number is an integer which is less than the sum of its proper divisors, excluding itself. thus, 12 is a superb number because 1, 2, 3, and 6 are its proper positive divisors and 1 + 2 + 3 + 4 + 6 > 12. the next superb number is 18 < 1 + 2 + 3 + 6 + 9. the next two superb numbers are 20 and 24. write a function called superb that returns true if the argument passed to it is a superb number and false otherwise.