new_contents: """
  climbs the inhertance tree using namespace links
  """
  
  def classtree(cls, indent):
      print('.' * indent, cls.__name__)
      for supercls in cls.__bases__:
          classtree(supercls, indent + 2)
  
  def instancetree(inst):
      print("Tree of {0}".format(inst))
      classtree(inst.__class__, 2)
  
  def selftest():
      class A: pass
      class B(A): pass
      class C(A): pass
      class D(B, C): pass
      class E: pass
      class F(D, E): pass
  
      instancetree(B())
      instancetree(F())
  
  if __name__ == '__main__':
      selftest()
  
subject: add util to display an object inhertance structure