gistfile1.py

>>> def by_id(id, **kwargs):
...     print(id, kwargs)
...
>>> by_id({'id': 1, 'foobaz': 2, 'bazfoo': 3})
{'foobaz': 2, 'bazfoo': 3, 'id': 1} {}

>>> by_id(**{'id': 1, 'foobaz': 2, 'bazfoo': 3})
1 {'foobaz': 2, 'bazfoo': 3}

>>> by_id(1, **{'id': 1, 'foobaz': 2, 'bazfoo': 3})
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: by_id() got multiple values for argument 'id'