Crash in grader statistics computation

[inducer]

Traceback (most recent call last):
  File "/home/andreas/relate/.venv/lib/python3.12/site-packages/django/core/handlers/exception.py",
line 55, in inner
    response = get_response(request)
               ^^^^^^^^^^^^^^^^^^^^^
  File "/home/andreas/relate/.venv/lib/python3.12/site-packages/django/core/handlers/base.py", line 197, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/andreas/relate/course/utils.py", line 821, in wrapper
    response = f(pctx, *args, **kwargs)
               ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/andreas/relate/course/grading.py", line 490, in show_grader_statistics
    pages = sorted(pages)
            ^^^^^^^^^^^^^

Exception Type: TypeError at /course/cs450-f24/grading/statistics/hw-1/
Exception Value: '<' not supported between instances of 'int' and 'NoneType'
Raised during: course.grading.show_grader_statistics