title: Django: Easily add extra manager for child class, still use default manager from AbstractBase
body: <p>This question is about the last example on <a href="http://docs.djangoproject.com/en/dev/topics/db/managers/#custom-managers-and-model-inheritance" rel="nofollow noreferrer">Custom managers and model inheritance</a>.</p>
  
  <p>I want to be able to do something similar to the following:</p>
  
  <pre><code>class ExtraManagerModel(models.Model):
  # OtherManager class supplied by argument shall be set as manager here
  
      class Meta:
          abstract = True
  
  class ChildC(AbstractBase, ExtraManagerModel(OtherManager)): # That doesn't work, something like that
      ...
      # Default manager is CustomManager, but OtherManager is
      # also available via the "extra_manager" attribute.
  </code></pre>
  
  <p>The whole purpose of this is that I don't want to write an <code>ExtraManagerModel</code> class for every overwritten manager in order to keep the default manager of the parent class (<code>AbstractBase</code>).</p>
  
  <p>Any ideas how this can be acheived?</p>