public function save(ExpenseListInOverview $readModel)
 {
     if (!isset($this->expenseLists[$readModel->getAccountId()])) {
         $this->expenseLists[$readModel->getAccountId()] = [];
     }
     $this->expenseLists[$readModel->getAccountId()][] = $readModel;
 }
 public function save(ExpenseListInOverview $readModel)
 {
     $this->collection->save($readModel->serialize());
 }