public async Task <IReadOnlyCollection <SettlementModel> > GetAsync(string clientId = null) { IReadOnlyCollection <Settlement> settlements; if (string.IsNullOrEmpty(clientId)) { settlements = await _settlementService.GetAllAsync(); } else { settlements = await _settlementService.GetByClientIdAsync(clientId); } return(Mapper.Map <SettlementModel[]>(settlements)); }