title: Why are trailing commas allowed in a list?
body: <p>I am curious why in Python a trailing comma in a list is valid syntax, and it seems that Python simply ignores it:</p>
  
  <pre><code>&gt;&gt;&gt; ['a','b',]
  ['a', 'b']
  </code></pre>
  
  <p>It makes sense when its a tuple since <code>('a')</code> and <code>('a',)</code> are two different things, but in lists?</p>