Hi. Please check if you did any of these:
- renamed your notebook
- renamed any of the variables
- imported any additional packages
Those are usually the reasons for that grader error. If you want to get a fresh copy of the notebook, you can follow the instructions here under Jupyter Lab.
If you submitted with the default filename (i.e. C3capstone_Assignment.ipynb) and sure that you did not rename any of the variables or imported any additional packages, you can send your notebook via direct message so we can investigate. You can click my name then the blue Message button. Thank you.