public async Task <ActionResult> MedicineCourse(int id)
        {
            if (id == 0)
            {
                throw new NullReferenceException("medicine course  not found");
            }
            if (!_context.Medicines.Any())
            {
                throw new NullReferenceException("medicine no entries");
            }
            var medicines = await _medicineService.GetByForeignKey(id);

            return(Ok(medicines ?? new List <Medicine>()));
        }