I didn't mean you "must be inside of a function". If you call `Process.put(:something, 10)`, any references you have to whatever was already in the process dic

I didn't mean you "must be inside of a function". If you call `Process.put(:something, 10)`, any references you have to whatever was already in the process dictionary will not have changed, and the only way to "observe" that there was some mutating state is that now subsequent calls to `Process.get(:something)` return a different value than it would have before. So with immutable variables, there is a strict contract for observing mutation.