It was, but that is not guaranteed and may stop being true due to work on subinterpreters, new memory managers, and heap types. Also, it used to be true that `

It was, but that is not guaranteed and may stop being true due to work on subinterpreters, new memory managers, and heap types. Also, it used to be true that ``frozenset() is frozenset()``, but that was lost in the war on singletons and global state.