title: Check if list contains a type?
body: <p>What is the fastest way I can check for a certain types existence in a list?</p>
  
  <p>I wish I could do the following:</p>
  
  <pre><code>class Generic(object)
      ... def ...
  class SubclassOne(Generic)
      ... def ...
  class SubclassOne(Generic)
      ... def ...
  
  thing_one = SubclassOne()
  thing_two = SubclassTwo()
  list_of_stuff = [thing_one, thing_two]
  
  if list_of_stuff.__contains__(SubclassOne):
      print "Yippie!"
  </code></pre>
  
  <p>EDIT: Trying to stay within the python 2.7 world. But 3.0 solutions will be ok!</p>