[4,5] means function(4)==5
[5,5] means function(5)==5
[4,5] means function(4)==5
f(4) and f(5) have diferent inputs, but they can return the same result.

Test.assertEquals(isFunction([[4,5], [5,5], [4,5]]),true)
This one?
Why it should be false?

Hi Yaprak,
I've checked my test cases and the array that you provided.
Everything is fine, the expected result for array is 6.
Can you please try to submit again, all tests ara randomly generated, so you should see a different result. Moreover there are predefined test cases that you can try by your own.

Hi, definitely it should be 6 for the provided array. I will check and fix it during a day. Thank you for spotting it.