class Request:
  ...

def with_request(f: Callable[..., R]) -> Callable[..., R]:
  def inner(*args: object, **kwargs: object) -> R:
    return f(Request(), *args, **kwargs)
  return inner

@with_request
def takes_int_str(request: Request, x: int, y: str) -> int:
  # use request
  return x + 7

takes_int_str(1, "A")
takes_int_str("B", 2) # fails at runtime