Fallback to FileContentsManager to support older notebook versions

[153957]

Since jupytext 1.1.0 support for notebook 4.4.1 is broken. That is since this fix: #210 ( 9d9b1e8 ), because that imported module does not exist in notebook 4.4.1. Could a fallback (in case of ImportError) to FileContentsManager be added? or at least made explicit that older versions of notebook are no longer supported.

[mwouts]

Hello @153957 , thanks for letting me know. Indeed we could implement a fallback. I will give it a try soon.

[153957]

In the mean time I have been upgrading the code where I encountered this problem to the newer notebook 5.x.x, so it is no longer an issue for me. However, a fix and/or a clear supported version list in the readme would still be useful.

[mwouts]

Sure! Upgrading notebook is a solution. Still, as you mention, catching the import error should be fairly easy, and you may not be the only person finding this issue, so I do prefer to provide a fallback...

[mwouts]

This is included in the latest release:

pip install jupytext==1.1.1