public async Task <CustomerDto> Handle(AddContractCommand request, CancellationToken cancellationToken) { var customer = await _customerRepository.GetById(request.CustomerId); if (customer == null) { return(null); } var contract = _mapper.Map <Contract>(request); contract.Customer = customer; contract = await _contractRepository.Create(contract); await _customerRepository.AddContract(contract); return(_mapper.Map <CustomerDto>(customer)); }