jupytext --to python does not work (--to py does)

[stared]

After typing in the command line jupytext --to python my_notebook.ipynb I got an error:

jupytext.formats.JupytextFormatError: No format associated to extension '.python'```

At the same time `jupytext --to py my_notebook.ipynb` works like a charm (generating the *light* python file).

I guess it is an issue with README.md, not the package.

[mwouts]

That's right! Thanks @stared for reporting this. I think the --to python used to work but only a very long time ago... let me fix this...

[mwouts]

I confirm that the --to argument must now be either notebook, markdown or rmarkdown, or an extension, or a format description (ext:format_name), with possibly a suffix/prefix. Indeed python is not any more part of the list - I will update the readme. Thanks @stared

[stared]

Thanks you a lot, @mwouts!