title: How the following python string are generated?
body: <p>I am reading this <a href="http://wsgi.tutorial.codepoint.net/parsing-the-request-get" rel="nofollow noreferrer"> wsgi document</a>, I can not understand how the response_body is generated.</p>
  <pre><code>    {
          response_body = html % { # Fill the above html template in
          'checked-software': ('', 'checked')['software' in hobbies],
          'checked-tunning': ('', 'checked')['tunning' in hobbies],
          'age': age or 'Empty',
          'hobbies': ', '.join(hobbies or ['No Hobbies?'])
      }
  </code></pre>
  <p>Can anyone explain the python syntax?</p>
  <pre><code>'checked-software': ('', 'checked')['software' in hobbies],
  </code></pre>