public async Task <IActionResult> ExponentiationPost(double number)
        {
            _logger.LogInfo($"[ExponentiationPost] number: {number}");

            CalcResult calcRes = null;

            try
            {
                calcRes = new CalcResult(_calcService.Exp(number));
                _calcResRepo.Add(calcRes);
                await _calcResRepo.SaveChangesAsync();
            }
            catch (Exception ex)
            {
                _logger.LogError($"[SubtractionPost] error: {ex.Message}, stack: {ex.StackTrace}, innerException: {ex.InnerException?.Message}");
                return(BadRequest(ex.Message));
            }

            _logger.LogInfo($"[ExponentiationPost] result: {calcRes?.Result}, Id: {calcRes?.Id}");

            return(Ok(calcRes.Id));
        }