title: Override Python's 'in' operator?
body: <p>If I am creating my own class in Python, what function should I define so as to allow the use of the <code>in</code> operator, e.g.</p>
  <pre><code>class MyClass(object):
      ...
  
  m = MyClass()
  
  if 54 in m:
      ...
  </code></pre>