title: how to use Flask Jinja2 url_for with multiple parameters
body: <p>I have a problem while using <code>jinja2</code> <code>url_for()</code> function.</p>
  
  <p>I have a route like this:</p>
  
  <pre><code>@app.route('/article/&lt;int:article_id&gt;/&lt;url_title&gt;/', methods=['GET'])
  def article_page(article_id, url_title):
      article = Article.query.get(article_id)
      if article == None:
          abort(404)
      return render_template('article.html', article=article)
  </code></pre>
  
  <p>in jinja template file,i want to create a url which links to article_page,so i write like this:</p>
  
  <pre><code>&lt;h5&gt;
    &lt;a href="{{ url_for('article_page',article_id=article.id,url_title=article.url_title) }}"&gt;{{ article.title }}&lt;/a&gt;
  &lt;/h5&gt;
  </code></pre>
  
  <p>but when I run this page, I get a error:</p>
  
  <pre><code>raise BuildError(endpoint, values, method)
  BuildError: ('article_page', {'article_id': 1}, None)
  </code></pre>
  
  <p>It seems like that the second parameter <code>url_title</code> missing.
  How can I use <code>url_for()</code> with multiple parameters correctly?</p>