title: Make string format ignore 'None'
body: <p>Is there a way in python such that when you do</p>
  
  <pre><code>foo = "foo"
  bar = None
  "{} {}".format(foo, bar)
  </code></pre>
  
  <p>it doesn't print None as the value of bar?</p>
  
  <p>ie. It should result in <code>"foo "</code> and not <code>"foo None"</code></p>