What this article ignores is that in practice one must read the source code to understand the function. You can be reasonably certain that the Python function doesn&#x27;t harm your grandmother that way. I understand that strong functional programming is going to catch type errors at compile time and force constraints on the values in your program but it&#x27;s quite rare that I&#x27;ve encountered a <i>type</i> error in a Python program.<p>What I most often encounter are <i>logic</i> errors. We don&#x27;t write formal specifications for safety-critical code often enough. Your program will still have errors of this kind if you don&#x27;t think clearly enough before you start writing code.<p>There are nice things strong, static typing of the functional variety offers certainly -- but it&#x27;s not a hammer that is particularly useful at cutting boards. There are plenty of cases where a dynamic type system is good enough or even ideal.