I am getting score 80 in the programming assignment of week 3 of the second course. Please help

Here is a thread with a checklist of the most common errors on that function.

If that doesn’t help, please note that you have not shown us what your actual answer is to the test case in any of the previous posts here. That might be helpful to know. Try running the actual test cell in the notebook, instead of the grader, and then show us the full output you are getting.