For what do you plan to use Python? Depending on your answer programming challenges may not even be your best way forward.
Creating automation scripts and webscraping
So why do you think you need to do Python coding challenges?
It's fine if you enjoy that stuff but if you really want to learn how to write quality automation scripts or get into webscraping then you should work on projects specific to that. Coding challenges wouldn't make you better at those things.
P.S. I used to participate in algorithmic coding challenges on sites like TopCoder (circa 2004) so I'm certainly not against those things.
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