primes [ for prime in primesprint(primesimpler for index in range(len(primes))print(primes[index]equivalent what good is list of valid indicesthere are two ways to step through the values in list one is directlythis is the method we have met already the second is to step through the indices and to look up the corresponding value in the list these are equivalent and the first method we have already seen is shorter to write so why bother with the second