public async Task OnPost()
        {
            var start = YahooModel.StartDate.ToString("yyyy-MM-dd");
            var end   = YahooModel.EndDate.ToString("yyyy-MM-dd");

            YahooModel.StockData = await YahooClass.GetYahooStock(YahooModel.Ticker, start, end, YahooModel.Period);
        }
        public async Task OnGet()
        {
            YahooModel.Ticker    = "IBM";
            YahooModel.StartDate = DateTime.Parse("2020-10-01");
            YahooModel.EndDate   = DateTime.Parse("2020-11-01");
            YahooModel.Period    = "daily";
            var start = YahooModel.StartDate.ToString("yyyy-MM-dd");
            var end   = YahooModel.EndDate.ToString("yyyy-MM-dd");

            YahooModel.StockData = await YahooClass.GetYahooStock(YahooModel.Ticker, start, end, YahooModel.Period);
        }