title: python syntax error *args with optional arg
body: <p>Why is this a syntax error??  What is the appropriate way to do this thing?</p>
  
  <pre><code>&gt;&gt;&gt; def f(*args, option=None):
    File "&lt;stdin&gt;", line 1
      def f(*args, option=None):
                        ^
  SyntaxError: invalid syntax
  </code></pre>