title: TypeError: sequence index must be integer
body: <p>I just have a problem with adding between every 3 characters a ",".</p>
  
  <pre><code>print totalpoints
  points = ','.join([totalpoints[i:i+3] for i in range(0, totalpoints, 3)])
  </code></pre>
  
  <p>Output:</p>
  
  <pre><code>875
  TypeError: sequence index must be integer
  </code></pre>