Execute script in IDLE with parameters

[buran]

without knn(sys.argv) you don't need it. And again - if you put it at the top it will work, but if your knn.py is properly structured, the second line should go in 'if __name__ == '__main__': block

Concerning IDLE alternative for Linux ... probably PyCharm

did you read my second post? I used PyCharm in the past, but currently using VSCode on both Linux and Windows and I like it very much. PyCharm is too heavy compared to VSCode. For third time - look at the tutorial.
Of course it's up to you. There are people that use PyCharm for one reason or another.