title: Uninitialized value in Python?
body: <p>What's the uninitialized value in Python, so I can compare if something is initialized, like:</p>
  <pre><code>val
  
  if val == undefined ?
  </code></pre>
  <p>EDIT: added a pseudo keyword.</p>
  <p>EDIT2: I think I didn't make it clear, but say val is already there, but nothing is assigned to it.</p>