The fact that this is not obviously true in Python has been one of my favourite things about the language for years. Callers can do so much that the callee didn’t plan for, design, or implement. Proper first-class functions are great. Functools.partial is great. Binding via __get__ is great. Two argument iter is great. Compared to the other languages I get to use, Python is such a breathe of freedom in this area.
And all of those things are truly optional for a beginner (in a well-designed library). Even the semantics added by __get__ are natural and help users to avoid issues, despite the implementation complexity.
Introducing an error when an argument is provided by name just doesn’t fit into the category of making functions easier to call.