removeCowsFromGroup method Null safety
Implementation
void removeCowsFromGroup(List<Cow> targetCows, CowGroup? targetGroup) {
if (targetGroup == null) return;
_cows = _cows.map((cow) {
if (targetCows.contains(cow)) {
cow.groups.removeWhere((group) => group == targetGroup);
}
return cow;
}).toList();
notifyListeners();
}