docs: def list_node(self, tab_level=-1):
          """
          Lists the current Node and its children.
  
          Usage::
  
              >>> node_a = AbstractCompositeNode("MyNodeA")
              >>> node_b = AbstractCompositeNode("MyNodeB", node_a)
              >>> node_c = AbstractCompositeNode("MyNodeC", node_a)
              >>> print node_a.list_node()
              |----'MyNodeA'
                      |----'MyNodeB'
                      |----'MyNodeC'
  
          :param tab_level: Tab level.
          :type tab_level: int
          :return: Node listing.
          :rtype: unicode
          """
  
          output = ""
          tab_level += 1
          for i in range(tab_level):
              output += "\t"
          output += "|----'{0}'\n".format(self.name)
          for child in self.__children:
              output += child.list_node(tab_level)
          tab_level -= 1
          return output