Help! Problem with submit Programming Assignment: Transfer Learning with MobileNet

All the test cases passed on the notebook. But the auto grader gave the programming assignment grade 0/100.
Auto grader output shows: Cell #6. Can’t compile the student’s code. Error: AttributeError(“‘NoneType’ object has no attribute ‘add’”).

You might be affected by the problem that Coursera is trying to solve.

See this thread.