ChangeNotifier listeners and dispose. Memory leaks?

I am curious if creation of new objects removes all attached listeners. Here it is simple code:

class Notifier extends ChangeNotifier {}

final notifier = Notifier();

for (int i = 0; i < 2; i++) {
  // Should I remove listeners before creation new instance of `Notifier`?
  // Or new instantiaion assumes that all listeners attached to object will be removed?
  notifier?.removeListener(_listener);
  notifier = Notifier();
  notifier.addListener(_listener);
}

void _listener() {}