pop method
Implementation
void pop(HarePage p) {
if (!_children.contains(p)) return;
while (_children.isNotEmpty && _children.removeLast() != p) {}
updateState();
}
void pop(HarePage p) {
if (!_children.contains(p)) return;
while (_children.isNotEmpty && _children.removeLast() != p) {}
updateState();
}