Give them a string, they return a table or function. Give them the table or function, they return a string.
It’s a useful technique that you can only apply if your hashmap can map anything to anything.
Any hashmap will have problems with storing mutable objects, where the hash value itself can change after the object has been stored, causing some very unwanted paradoxes.
And that is the problem with Python dicts as keys.
I just assumed it was the former, based on the fact that dicts are disallowed as keys.
The reason for that choice is because the object is mutable.