title: convert a list into a single string consisting with double quotes and separated by comma
body: <p>I have met a problem to convert a list: <code>list=['1','2','3']</code> into <code>' "1","2","3" '</code>.</p>
  
  <p>My code is:    </p>
  
  <pre><code>str(",".join('"{}"'.format(i) for i in list))
  </code></pre>
  
  <p>but my output is:
      <code>"1","2","3"</code> instead of <code>' "1","2","3" '</code></p>
  
  <p>May I have your suggestion? Thanks.</p>