Agentic AI grading issue

I am doing C1M3_Assignment in Agentic AI course, assignment tests pass successfully, but grading fails every time with the below error message:

Failed test case: generate_research_report_with_tools raised BadRequestError: Error code: 400 - {‘error’: {‘message’: ‘you must provide a model parameter’, ‘type’: ‘invalid_request_error’, ‘param’: None, ‘code’: None}}.
Expected:
no exception,
but got:
Error code: 400 - {‘error’: {‘message’: ‘you must provide a model parameter’, ‘type’: ‘invalid_request_error’, ‘param’: None, ‘code’: None}}.

Did you save your notebook before you submitted it for grading?

It says here you have to provide a model name; usually, this is something like gpt-mini…