public IActionResult CreateValuePair(int chartId,
                                             [FromBody] ValuePairForCreationDto valuePair)
        {
            if (valuePair == null)
            {
                return(BadRequest());
            }

            if (!ModelState.IsValid)
            {
                return(BadRequest(ModelState));
            }

            if (!_chartRepository.ChartExists(chartId))
            {
                return(NotFound());
            }

            var mapValuePair = Mapper.Map <Entities.ValuePair>(valuePair);

            _chartRepository.AddValuePairForChart(chartId, mapValuePair);

            if (!_chartRepository.Save())
            {
                return(StatusCode(500, "A problem happened while handling your request."));
            }

            var createdValuePairToReturn = Mapper.Map <ValuePairDto>(mapValuePair);

            return(CreatedAtRoute("GetValuePair", new
                                  { chartId, id = createdValuePairToReturn.Id }, createdValuePairToReturn));
        }