C2_W4 practice lab - exerxice4 error 'check implementation'

I complete the code and pass the test case (which answer is ‘2’)
But when I submit the code, the message says ‘incorrect’

so I change my code similar to the hint, and I still get same problem.

I got question 1,2,3 correct, so I don’t think previous codes(1,2,3) have problem,
so I think it’s not dependency problem

Could you give me a hand ?

Hi @minsup19 !

Can you send me your code in a direct message and I’ll take a look