As Tom points out, just passing one set of tests is not a guarantee of success. In this scenario there are two overall possibilities:
- Your code is not general, meaning it passes the tests in the notebook, but fails the different tests that the grader uses. Ways this could happen would be referencing global variables from within the body of your functions or hard-coding the dimensions of objects.
- There is something structural wrong with your notebook that interferes with the grader’s operation. Modifying things outside the “YOUR CODE HERE” sections can cause this. Or uploading an old notebook from github or the like.
If you have thought hard about option 1) and haven’t come up with anything yet, it would be worth getting a clean notebook (using this thread) and then carefully copy/pasting just your solution code over to the “YOUR CODE HERE” sections and then submitting again and seeing if that helps.
If neither of the above work, then let us know and there are yet other ways to proceed.