How to use the robotframework.models.webtest_task.objects.all function in robotframework

def add_task_webcase_test(request):
    username = request.session.get('user', '')
    tasks = webtest_task.objects.all()
    if request.method == "POST":
        objs = request.POST.get("objstring")
        obj = json.loads(objs)
        for i in range(0, len(obj)):
            id=int(obj[i]['id'])
            webcase_models = obj[i]['webcase_models']
            webcasename = obj[i]['webcasename']
            webcasedesc = obj[i]['webcasedesc']
            webtest_task.objects.create(case_id=id,task_modelname=webcase_models,task_casename=webcasename,task_stepdesc=webcasedesc)
        return  render(request, "webcase_periodic_task.html",{"user": username, "tasks": tasks})

def run_webcase_immediately(request):
    username = request.session.get('user', '')
    tasks = webtest_task.objects.all()
    if request.method == "POST":
        write_name_txt()
        time.sleep(2)
        get_task_stepdata()
        time.sleep(1)
        run_in_terminal()
    return render(request, "webcase_periodic_task.html", {"user": username, "tasks": tasks})

def webUI_periodic_task(request):
    username = request.session.get('user','')
    tasks = webtest_task.objects.all()
    cases = Webcase.objects.all()
    singel_tasks = webtest_task.objects.get_queryset().order_by('task_id')
    paginator = Paginator(singel_tasks, 15)  # 生成paginator对象,设置每页显示15条记录
    page = request.GET.get('page', 1)  # 获取当前页为第1页
    currentPage = int(page)  # 把当前页转换成整数
    try:
        singel_tasks = paginator.page(page)  # 获取当前页码数的记录列表
    except PageNotAnInteger:
        singel_tasks = paginator.page(1)  # 如果输入的页数不是整数则显示第1页内容
    except EmptyPage:
        singel_tasks = paginator.page(paginator.num_pages)  # 如果输入的的页数不在系统的页数中，则显示最后一页
    return  render(request, "webcase_periodic_task.html", {"user": username, "singel_tasks": singel_tasks,"cases":cases,"tasks": tasks})