Hi there, Following this post //www.freelists.org/post/nuitka-dev/Nuitka-0325pre4-reformulated-or-and-and I realized that pythran does not support the `or' and `and' operators the way python does. Not a big deal as we can use intrisic to simulate their behavior and use something like a or b -> (a?a:b) instead. An optimization could be to detect that (a or b) is only used for a test, and thus we could generate a || b instead of the more expensive python test. Looks a lot like the on-going work around range/xrange ! -- serge