I mostly agree, but for short one liners and where there will be no reuse elsewhere, instead of a function I prefer; something_is_valid = something > 0 and s

I mostly agree, but for short one liners and where there will be no reuse elsewhere, instead of a function I prefer; something_is_valid = something > 0 and something != foo and something > bar if something_is_valid: # .... It achieves the same thing without needing to scroll.