> I'd be surprised if other implementations passed immutable objects by value I'm thinking of MicroPython here - it supports several pointer-tagging schemes, i

> I'd be surprised if other implementations passed immutable objects by value I'm thinking of MicroPython here - it supports several pointer-tagging schemes, in which "references" might be actual pointers or might instead be immutable values stored directly. For example, using the NaN-boxing scheme, MicroPython references might actually be inline `float`s, small `int`s, or constants like `None`, `True` or `False`.