Can you maybe extend the CSI comment about why Literal needs to be treated here as well?

To me, it looks rather natural in this sequence and it might look a bit strange if I explain only the Literal bit:

(
            "<class 'typing._GenericAlias'>",
            "<class 'types.GenericAlias'>",
            "<class 'typing._LiteralGenericAlias'>",
        )

They're all Generic aliases.

OTOH, it's hard to imagine that we'll ever put a telegram class inside a literal. Something like:

Persistence = Literal["PicklePersistence", "DictPersistence"]

In this case, I could just create a separate condition for Literal and skip it altogether without even checking what's inside.