public async Task <IEnumerable <Expense> > GetAllExpensesForBillAsync(int billId)
 {
     try
     {
         return(await _expenseRepository.GetAllExpensesForBillAsync(billId));
     }
     catch (SqlException e)
     {
         Logger.Instance.Error(e);
         return(null);
     }
     catch (Exception ex)
     {
         Logger.Instance.Error(ex);
         return(null);
     }
 }