I suspect this means that one of your functions does not pass one of the tests that the grader uses.
The grader uses different test cases than are used in the notebook.
Passing the tests in the notebook does not prove your code is perfect.
You can see which function had the problem by looking at the grader feedback.
Hello @MOHAMED_AZIZ2
Or is that a quiz?
At the top right corner of each question, it tells you how many points you have got out of the total for that question. Check them out and see which ones didn’t score full marks.
You might have missed some correct answers for some questions that require you to select multiple answers.
Cheers,
Raymond