"Your turn now - go on and change the following code to compute the sum of the numbers 1 through 5." If you input 15 and submit, it says the answer is correct.

"Your turn now - go on and change the following code to compute the sum of the numbers 1 through 5." If you input 15 and submit, it says the answer is correct. Do all online code courses just check for the retured value? How do these services deal with someone running sum(i for i in xrange(1000000000000000000))?