public async Task <IActionResult> Main()
        {
            var siniflar = await _sinifService.GetAll();

            var sinifList = new List <Dictionary <string, List <Dictionary <string, string> > > >();

            foreach (var sinif in siniflar)
            {
                var dersler = await _dersService.GetAllByFilter(I => I.SinifID == sinif.ID);

                var dersList = new List <Dictionary <string, string> >();
                foreach (var ders in dersler)
                {
                    var dersDic = new Dictionary <string, string>();
                    dersDic.Add("name", ders.Isim);
                    dersList.Add(dersDic);
                }
                var sinifDic = new Dictionary <string, List <Dictionary <string, string> > >();
                sinifDic.Add(sinif.SinifNumarasi.ToString(), dersList);
                sinifList.Add(sinifDic);
            }
            return(Ok(sinifList));
        }