Thanks to @retnikt for opening #7422. This issue is tracking that and will have an accompanying PR that more broadly fixes the issue.

When typing Python code, the special *args and **kwargs params are typed based on their contents, not what they actually are (a tuple, and a dict) e.g.

def foo(thing: int, *args: str):
...
def bar(thing: int, *args: str, **kwargs: Union[int, float]):
...

bar(-3, "G", spam=80, eggs=4.4)
foo(44, "abc", "xyz")
And in this case, the types are passed to a different func (Query.init) which has specific arguments, so it is best to not give **kwargs a type, or, better, copy the parameters of that function (but I haven't done this here).
This also applies to Transaction.
PS I know this is a stupidly minor change but it annoys me, having to write noinspection PyTypeChecker before every datastore query.
😄