public void GenerateReport(IEnumerable <StudentDto> students)
    {
        Excel.Application app = new Excel.Application();
        app.DisplayAlerts = false;
        Excel.Workbook   book_template  = app.Workbooks.Open(@"шаблон_отчета.xlsx");
        Excel._Worksheet sheet_template = book_template.Sheets["отчет"];
        foreach (var ob in students)
        {
            //1. Создаем объкт LearnerReport из БД
            LearnerReport report = new LearnerReport
            {
                SNS         = $"{ob.surname} {ob.name} {ob.SecondName}",
                SchoolName  = ob.SchoolName,
                ClassName   = ob.ClassName,
                TestResult5 = ob.TestResult5
            };
            //2. Экспорт объкта LearnerReport в шаблон xlsx
            sheet_template.Range["C4"].Value2 = report.SNS;
            sheet_template.Range["C5"].Value2 = report.SchoolName;
            sheet_template.Range["C6"].Value2 = report.ClassName;
            sheet_template.Range["C9"].Value2 = report.TestResult5;
            //3. Сохраняем полученный файл в .pdf на рабочем столе
            string file_name = $@"{Environment.GetFolderPath(Environment.SpecialFolder.Desktop)}\{report.SNS}.pdf";
            sheet_template.ExportAsFixedFormat(Excel.XlFixedFormatType.xlTypePDF, file_name);
        }

        book_template.Close(0);
        book_template = null;
        app.Quit();
        app = null;
    }