One of the ideas of Python's design philosophy is "There should be one ... obvious way to do it." (PEP 20), but that can't always be true. I'm specifically referring to (simple) if statements versus boolean evaluation. Consider the following: if words: self.words = words else: self.words = {} versus self.words = words or {} With such a simple situation, which is preferable, stylistically speaking? With more complicated situations one would choose the if statement for readability, right?