Given that several projects exist in python to do this… I guess if you know about types at runtime, it is possible to do it. I write one of them (typedload).

Given that several projects exist in python to do this… I guess if you know about types at runtime, it is possible to do it. I write one of them (typedload). If it's a union, it has a bunch of heuristics to guess right at the 1st try, but otherwise it will just try them all.