def print_arg(**kwargs):
    print(kwargs.pop('key'))
kwargs['list'].pop()
kwargs['dict'].pop('a')
mydict = {'key': 'value', 'list': [2, 3, 4, 5], 'dict': {'a': 1, 'b': 2}}
print_arg(**mydict)
print(mydict)
Mutability of the **kwargs argument in Python