def store(node)
         if !node.nil?
            @children.push(node) if !@children.include?(Node)
            node.parent = self if node.parent != self
         end
         node
      end
def store(node)
         if !node.nil?
            @children.push(node) if !@children.include?(Node)
            node.parent = self if node.parent != self
         end
         node
      end
This is the constructor for the ContainerNode class.

 ==== Parameters
 parent::     A reference to the parent node that owners the new
              ContainerNode object.
 This method adds a new node element to the end of the list of nodes
 maintained by a ContainerNode object. Nil objects are ignored.

 ==== Parameters
 node::  A reference to the Node object to be added.