public async Task <ExpenseDto> GetAsync(Guid settlementId, Guid userId, Guid expenseId, Guid currentUserId)
{
var userExpenses = await _settlementRepository.GetExpensesOrFailAsync(settlementId, userId, currentUserId);
var expense = userExpenses.SingleOrDefault(x => x.Id == expenseId);
if (userExpenses == null)
{
throw new Exception($"Expense with id: '{expenseId}' does not exist.");
}
return(_mapper.Map <ExpenseDto>(expense));
}