Hi @mahmoud_ahc, in general it is a bad idea to change the expected public tests results, it may give you the wrong impression that you will pass the tests in the grader when submitting your notebook.

As indicated by @nero that function is testing the sigmoid which is not equal to math.exp as you suggest in your post. Please refer to the right formula.

since the real result is 2.718281828459045 as shown by the test done on the target, then it raises error in the second test as failed assertion due to difference between the actual result and written number in the test function.

@mahmoud_ahc you are mixing exponent with the whole sigmoid function. The exponent is just a part of the sigmoid function. Check out the sigmoid function formula again.