title: Join string before, between, and after
body: <p>Suppose I have this list:</p>
  
  <pre><code>lis = ['a','b','c','d']
  </code></pre>
  
  <p>If I do <code>'x'.join(lis)</code> the result is:</p>
  
  <pre><code>'axbxcxd'
  </code></pre>
  
  <p>What would be a clean, simple way to get this output?</p>
  
  <pre><code>'xaxbxcxdx'
  </code></pre>
  
  <p>I could write a helper function:</p>
  
  <pre><code>def joiner(s, it):
      return s+s.join(it)+s
  </code></pre>
  
  <p>and call it like <code>joiner('x',lis)</code> which returns <code>xaxbxcxdx</code>, but it doesn't look as clean as it could be. Is there a better way to get this result?</p>