title: Reverse for 'update_comment' with arguments '('',)' not found. 1 pattern(s) tried: ['comment\\/(?P<news_pk>[0-9]+)$']
body: <p>I'm coding a news site.Now I'm detailing with the comment post function.And meet the issue says:</p>
  
  <pre><code>Reverse for 'update_comment' with arguments '('',)' not found. 1 pattern(s) tried: ['comment\\/(?P&lt;news_pk&gt;[0-9]+)$']
  </code></pre>
  
  <p>I have tried many ways and times but still can't solve it and I can't find any wrong with my code.And really need your help.</p>
  
  <p>The comment post function is in the news_detail.html. There are two important apps in my project <strong>news</strong> and <strong>operation</strong> comment models is under <strong>operation</strong></p>
  
  <p>Here is my <strong>root urls.py</strong>:</p>
  
  <pre><code>path('news', include(('news.urls', 'news'), namespace="news")),
  path('', include(('operation.urls', 'operation'), namespace="operation")),
  </code></pre>
  
  <p>Here is the <strong>news/urls.py</strong></p>
  
  <pre><code>path('-&lt;int:news_pk&gt;', newsDetailView, name="news_detail")
  </code></pre>
  
  <p>Here is the operation/urls.py:</p>
  
  <pre><code>path('comment/&lt;int:news_pk&gt;', views.update_comment, name="update_comment"),
  </code></pre>
  
  <p>Here is the <strong>news/view.py</strong></p>
  
  <pre><code>def newsDetailView(request, news_pk):
      news = News.objects.get(id=news_pk)
      title = news.title
      author = news.author_name
      add_time = news.add_time
      content = news.content
      category = news.category
      tags = news.tag.annotate(news_count=Count('news'))
  
      all_comments = NewsComments.objects.filter(news=news)
      return render(request, "news_detail.html", {
          'title': title,
          'author': author,
          'add_time': add_time,
          'content': content,
          'tags': tags,
          'category': category,
          'all_comments': all_comments,
      })
  </code></pre>
  
  <p>Here is <strong>operation/views.py</strong></p>
  
  <pre><code>def update_comment(request, news_pk):
      news = News.objects.get(id=news_pk)
      comment_form = CommentForm(request.POST or None)
      if request.method == 'POST' and comment_form.is_valid():
          if not request.user.is_authenticated:
              return render(request, 'login.html', {})
          comments = comment_form.cleaned_data.get("comment")
          news_comment = NewsComments(user=request.user, comments=comments, news=news)
          news_comment.save()
  
          return render(request, "news_detail.html", {
              'news_comment': news_comment，
              'news'：news
          })
  </code></pre>
  
  <p>And here is the news_detail.html:</p>
  
  <pre><code>{% if user.is_authenticated %}
  
  &lt;form method="POST" action="{% url 'operation:update_comment' news.pk %}"&gt;{% csrf_token %}              
  
  &lt;textarea id="js-pl-textarea" name="comment"&gt;&lt;/textarea&gt;      
  
  &lt;input type="submit" id="js-pl-submit" value="发表评论"&gt;&lt;/input&gt;&lt;/form&gt;
  </code></pre>