Binding Arguments to Parameters

How it works

1. The parser checks the call first: a positional after a keyword, or a repeated keyword, is a SyntaxError before anything runs.
2. At the call site, *list spreads into separate positional arguments and **dict into keyword arguments.
3. Positional arguments fill the parameters left to right; leftovers go into the *args tuple.
4. Each keyword matches a parameter by exact name (a second value is 'got multiple values'); unknown names go into **kwargs or raise 'unexpected keyword argument'.
5. Then: too many positionals, or a required parameter still empty, is a TypeError; otherwise defaults fill the rest.
6. Defaults are evaluated once, at def time: a list default is the same object in every call.

Default run (13 steps): def greet(…) runs once: it creates the function and evaluates its default values right now. Then the call greet('Ann', 'Hi', *[7, 8], sep='-', mood='happy') starts. … Done. Printed: {'name': 'Ann', 'greeting': 'Hi', 'sep': '-', 'args': (7, 8), 'kwargs': {'mood': 'happy'}}.