title: Set an object's superclass at __init__?
body: <p>Is it possible, when instantiating an object, to pass-in a class which the object should derive from?</p>
  
  <p>For instance:</p>
  
  <pre><code>class Red(object):
      def x(self):
          print '#F00'
  
  class Blue(object):
      def x(self):
          print '#00F'
  
  class Circle(object):
      def __init__(self, parent):
          # here, we set Bar's parent to `parent`
          self.x()
  
  class Square(object):
      def __init__(self, parent):
          # here, we set Bar's parent to `parent`
          self.x()
          self.sides = 4
  
  red_circle = Circle(parent=Red)
  blue_circle = Circle(parent=Blue)
  blue_square = Square(parent=Blue)
  </code></pre>
  
  <p>Which would have similar effects as:</p>
  
  <pre><code>class Circle(Red):
      def __init__(self):
          self.x()
  </code></pre>
  
  <p>without, however, affecting other instances of <code>Circle</code>.</p>