Hello,

I came to Pydantic via FastAPI, which uses Pydantic at its core. One feature I'm enamoured with is the idea of query parameter models, and it works like this: Say you have a model with a:str and b:int, then you can tell FastAPI that an API endpoint takes e.g. GET query parameters a:str and b:int simply by telling FastAPI that the model describes valid query string parameters. The same works for cookies and headers.

This got me thinking: say I have two models describing parameters:

class One(BaseModel):
    a: str

class Two(BaseModel):
    b: int

Assume furthermore I want to expose a function that takes a and b as parameters, is there a way to reuse those BaseModel derivatives for typing a **kwargs dictionary, similar to if the above two were TypedDict definitions? Basically something like Unpack that works with Pydantic's BaseModel? Like so:

def some_function(**kwargs: Unpack[Concat[One, Two]]) -> None:
    ...

and that would mean that type checkers would type-check kwargs in the function call and warn if anything other than a:str and b:int was passed?

Looking forward to any insights or ideas how to achieve the above. Thank you!