title: How do I tell which modules have been mixed into a class?
body: <p>I have a class that has a number of modules that are mixed in with it based on some runtime criteria.</p>
  <p>I want to be able to get a list of which modules have been mixed into this class. How can you do that?</p>
  <p>UPDATE</p>
  <p>So when I said class I meant object as it is the object that is being extended at runtime using:</p>
  <pre><code>obj.extend(MyModule)
  </code></pre>
  <p>obj.included_modules and obj.ancestors don't exist so you can't get the modules that have been mixed in from there.</p>