title: Why is a trailing comma a SyntaxError in an argument list that uses *args syntax?
body: <p>Why can't you use a trailing comma with <code>*args</code> in Python?  In other words, this works</p>
  
  <pre><code>&gt;&gt;&gt; f(1, 2, b=4,)
  </code></pre>
  
  <p>But this does not</p>
  
  <pre><code>&gt;&gt;&gt; f(*(1, 2), b=4,)
    File "&lt;stdin&gt;", line 1
      f(*(1, 2), b=4,)
                     ^
  SyntaxError: invalid syntax
  </code></pre>
  
  <p>This is the case with both Python 2 and Python 3.</p>