Decorator to return default argument values
I am not sure how critical this use case is, but when any of your arguments have a dictionary value, you have that dictionary items used as keyword arguments for the function:

In [1]: @return_kwargs
   ...: def example(arg1):
   ...:     pass
   ...: 

In [2]: arg1_value = {'arg3': 'value'}

In [3]: print(example(arg1_value))
{'arg3': 'value'}


In other words, arg3 here is printed as a keyword argument for the function but it was not actually unpacked into keyword arguments to the function at all - it was "sitting" inside the value of an arg1 positional argument.