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Python Performance: Why 'if not list' is 2x Faster Than Using len()
(blog.codingconfessions.com)
This is a most excellent place for technology news and articles.
If there is an alternative through which I can achieve the same intended effect and is a bit more safer (because it will verify that it has len implemented) I would prefer that to commenting. Also if I have to comment every len use of not that sounds quite redundant as len checks are very common