There is a grader error for in assignment 3 exercise 4. Link avaialble here: Issue
Hello @chiefaiofficer I couldnt reproduce the issue with exercise 4 since it can pass the grader. Note that e04 tag should be in the cell so the exercise could be graded.
Check if its missing and right click on the cell > notebook cells> add cell tag and type ex04. Hope it helps
sorted