Python list function argument names

Use the inspect module from Python's standard library (the cleanest, most solid way to perform introspection).

Specifically, inspect.getargspec(f) returns the names and default values of f's arguments -- if you only want the names and don't care about special forms *a, **k,

import inspect

def magical_way(f):
    return inspect.getargspec(f)[0]

completely meets your expressed requirements.

>>> import inspect
>>> def foo(bar, buz):
...     pass
... 
>>> inspect.getargspec(foo)
ArgSpec(args=['bar', 'buz'], varargs=None, keywords=None, defaults=None)
>>> def magical_way(func):
...     return inspect.getargspec(func).args
... 
>>> magical_way(foo)
['bar', 'buz']