    # File lib/facets/more/linkedlist.rb, line 145
            def push(v)
                    if @lookup.has_key?(v)
                            n = @lookup[v]
                            node_delete(n)
                            node_join(@tail.prev_node,n)
                            node_join(n,@tail)
                    else
                            n = Node.new(v,v,@tail.prev_node,@tail)
                            node_join(@tail.prev_node,n)
                            node_join(n,@tail)
                            @lookup[v] = n
                    end
                    v
            end