NameError: name 'CallbackHandler' is not defined


I worked through the notebook for lesson 2 using google cloud.
After installing fastai, fastbook and ipywidgets all cells executed without error.

To my surprise when I tried to execute the first cell from the lesson 2 clean notebook it gives me the error message: “NameError: ‘CallbackHandler’ is not defined”

This is despite the exact same content:

  • import fastbook
  • fastbook.setup_book()
    executes perfect in the lesson notebook.

Does somebody have an explanation for this??


see below for traceback and versions of fastai and fastcore

I guess you need to update fastai.

unfortunately updating fastai does not help. After uninstalling it each time I tried the latest and 4 previous versions. Always the same error message.
I also tried with different versions of fastbook. Always the same error message.

In PyPI I found that new versions for the fastai, fastcore and fastbook packages were created in the last days.
I assume the error is due to me using the latest versions of all 3.
Can somebody please advise which versions of:

  • fastai
  • fastcore
  • fastbook
    work together without error message on import??

thanks a lot