Python function annotation for easier argparse handling

mydecorators.py

#!/usr/bin/env python3
from functools import wraps
import inspect

def argparse_compatible(func):
    """Decorator that enables calling a function with its arguments or using an argparse.Namespace object.
    For example, the function
    
    @argparse_compatible
    def f(a, b, c):
        return None
    
    can be called via
    
    f(a, b, c)
    
    or via
    
    parser = argparse.ArgumentParser()
    parser.add_argument("-a")
    parser.add_argument("-b")    
    parser.add_argument("-c")
    args = parser.parse_args()
    
    f(args)    
    """
    @wraps(func)
    def wrapper(*args, **kwargs):
        if len(args) == 1 and type(args[0]) == argparse.Namespace:
            expected_args = inspect.signature(func).parameters.keys()
            args = {arg: getattr(args[0], arg) for arg in expected_args if hasattr(args[0], arg)}
            return func(**args)
        else:
            return func(*args, **kwargs)

    return wrapper