问提升TemplateDoesNotExist(template_name，chain=chain)

EN

Traceback (most recent call last):
....
raise TemplateDoesNotExist(template_name, chain=chain)
django.template.exceptions.TemplateDoesNotExist: None

TEMPLATES = [
{   ...
    'DIRS': [ os.path.join(BASE_DIR, 'templates')],}, 
  ...]

from django.views.generic import View
from django.shortcuts import render
from django.shortcuts import get_object_or_404
from .models import Post, Tag
from .utils import ObjectDetailMixin

def posts_list(request):
   posts = Post.objects.all()
   return render(request, "blog/index.html", context={'posts':posts})


class PostDetail(ObjectDetailMixin, View):
   model = Post
   tamplate = 'blog/post_detail.html'

class TagDetail(ObjectDetailMixin, View):
   model = Tag
   template = 'blog/tag_detail.html'

def tags_list(request):
   tags = Tag.objects.all()
   return render(request,'blog/tags_list.html',
   context={'tags': tags})

from django.shortcuts import render
from django.shortcuts import get_object_or_404
from .models import *

class ObjectDetailMixin:
    model = None
    template = None

def get(self, request, slug):
    obj = get_object_or_404(self.model,
    slug__iexact=slug)
    return render(request, self.template,
    context={self.model.__name__.lower():obj})

from django.contrib import admin
from django.urls import path, include


urlpatterns = [
    path('admin/', admin.site.urls),
    path('blog/', include('blog.urls')),
]

from django.urls import path
from .views import *

urlpatterns = [
    path('', posts_list, name='posts_list_url'),
    path('post/<str:slug>/', PostDetail.as_view(), 
name='post_detail_url'),
    path('tags/', tags_list, name='tags_list_url'),
    path('tag/<str:slug>', TagDetail.as_view(), name='tag_detail_url')
 ]

from django.db import models
from django.shortcuts import reverse
# Create your models here.
class Post(models.Model):
    title = models.CharField(max_length=150, db_index=True)
    slug = models.SlugField(max_length=150, unique=True)
    body = models.TextField(blank=True)
    tags = 
    models.ManyToManyField('Tag',blank=True,related_name='posts')
    date_pub = models.DateTimeField(auto_now_add=True)

   def get_absolute_url(self):
       return reverse('post_detail_url', kwargs={'slug':self.slug})

   def __str__(self):
       return self.title

 class Tag(models.Model):
     title = models.CharField(max_length=50)
     slug = models.SlugField(max_length=50,unique=True)

     def get_absolute_url(self):
         return reverse('tag_detail_url', kwargs={'slug': self.slug})

     def __str__(self):
         return self.title

<div class="card mb-4">
<div class="card-header">
  {{ post.date_pub}}
</div>
<div class="card-body">
  <h5 class="card-title">{{post.title}}</h5>
  <p class="card-text">{{post.body|truncatewords:10}}</p>
  <a href="{{ post.get_absolute_url }}" class="btn btn-light">Read</a>
</div>
<div class="card-footer text-muted">
  Tags:
  {% for tag in post.tags.all %}
    <a href="{{ tag.get_absolute_url }}"> {{ tag.title }}</a>
  {% endfor %}
 </div>