code: def is_derived (type, base):
      
      assert isinstance(type, basestring)
      assert isinstance(base, basestring)
      # TODO: this isn't very efficient, especially for bases close to type
      if base in all_bases (type):
          return True
      else:
          return False
docs: Returns true if 'type' is 'base' or has 'base' as its direct or indirect base.