How can I solve this :
First, please be sure you post in the correct forum for your course. You’ve posted in General Discussions, so we don’t know what course you are attending.
You can move your thread to the correct forum by using the “pencil” icon in the thread title.
Second, general guidance on using the notebooks:
- Whenever you open a notebook, always run all of the cells starting from the top. That’s where the resources and assets are loaded (such as the imported packages and the utility functions and test cases).