title: Negative form of isinstance() in Python
body: <p>How would I use a negative form of Python's isinstance()?</p>
  
  <p>Normally negation would work something like </p>
  
  <pre><code>x != 1
  
  if x not in y
  
  if not a
  </code></pre>
  
  <p>I just haven't seen an example with isinstance(), so I'd like to know if there's a correct way to used negation with isinstance().</p>