title: convert a set into string in python
body: <p>let say I got a set call x</p>
  
  <pre><code>x = set(['x','c','v','x','w','g'])
  
  print(', '.join(x)
  </code></pre>
  
  <p>I get </p>
  
  <pre><code>x,c,v,x,w,g
  </code></pre>
  
  <p>How can modify my code to get </p>
  
  <pre><code>x,c,v,x,w or g
  </code></pre>
  
  <p>change the last , to a or?</p>