code: def list_attributes(self):
          
  
          return [attribute for attribute, value in self.iteritems() if issubclass(value.__class__, Attribute)]
docs: Returns the Node attributes names.
  
          Usage::
  
              >>>	node_a = AbstractNode("MyNodeA", attributeA=Attribute(), attributeB=Attribute())
              >>> node_a.list_attributes()
              ['attributeB', 'attributeA']
  
          :return: Attributes names.
          :rtype: list