void updateGroups(List<String> vals, [ bool ignoreId = false ])

Source 

void updateGroups(List<String> vals, [bool ignoreId = false]) {
  if (ignoreId) {
    groups = vals.where((str)=>str != '').toList();
  } else {
    groups = [reqId]..addAll(vals.where((str)=>str != ''));
  }

}