public function whenCommitteeGoalChanged(CommitteeGoalChanged $event)
 {
     $committee = $this->committees->find((string) $event->committeeId());
     $committee = $committee->changeGoal($event->goal());
     $this->committees->save($committee);
 }
 protected function applyCommitteeGoalChanged(CommitteeGoalChanged $event)
 {
     $this->goal = $event->goal();
 }