Python doesn't have type safety to begin so those sort of checks have less utility to me and since json.loads returns a dictionary and python objects are effectively dictionaries you are pretty much done.
It does, if you want it to, with several typecheckers available.
For example if I'm going to use a value in a query, because I'm using parameterized queries the type conversion to string happens implicitly so type doesn't actually matter. If I get 2 or '2' it all ends up as '2' and the database infers type by the column type.
If I need something to be a integer and I don't trust the upstream system then you have to:
int(*number*)
On the other hand services that aren't actively utilizing data I write to be fairly agnostic about that data. "be conservative in what you do, be liberal in what you accept from others." is sort of how I aim.