docs: def get_attributes(self):
          """
          Returns the Node attributes.
  
          Usage::
  
              >>>	node_a = AbstractNode("MyNodeA", attributeA=Attribute(value="A"), attributeB=Attribute(value="B"))
              >>> node_a.get_attributes()
              [<Attribute object at 0x7fa471d3b5e0>, <Attribute object at 0x101e6c4a0>]
  
          :return: Attributes.
          :rtype: list
          """
  
          return [attribute for attribute in self.itervalues() if issubclass(attribute.__class__, Attribute)]