If this is supposed to be Pandas syntax the term would be lineterminator.
https://pandas.pydata.org/docs/reference/api/pandas.DataFrame.to_csv.html
Then you are using a community Python scripting extension. My suggestion would be to use the official one and read up how to use it.
You can send data directly from KNIME to Python and the other way round.
Then you can use your own .PY code (and Jupyter notebooks) from a KNIME Python node. You will have to make sure about the paths and data transfer. Here is a example how to do that.
And finally if you want the whole story about KNIME, Conda, Python and so on you can read my article: