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 theLiteral 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 forLiteral and skip it altogether without even checking what's inside.