为什么这段代码不会将任务追加到任务我一直在学习CS50课程，在我应用这段代码后，我没有看到预期的结果，我尝试了所有方法，但仍然表单不会追加到任务列表

from django.shortcuts import render
from django import forms
from django.http import HttpResponseRedirect
from django.urls import reverse

class NewTaskForm(forms.Form):
    task = forms.CharField(label="Task Text")
    
tasks = ['finish', 'study', 'reset']

# Create your views here.
def index(request):
    
    return render(request, "task/index.html",{
        "tasks":tasks
    })
    
def add(request):
    if request.method =="post":
        form = NewTaskForm(request.post)
        if form.is_valid():
            task = form.cleaned_data["task"]
            tasks.append(task)
            return HttpResponseRedirect(reverse("task:index"))
        else:
            return render(request, "task/add.html", {
                "form":form
            })
    return render(request, "task/add.html",{
        "form":NewTaskForm()
    })