sub tree_dag_node { my($tree) = Tree::DAG_Node -> new({name => 'Root'});

        $tree -> attributes({uid => 0});

        my($count) = 0;

        my(%node);

        for (qw/H I J K L M N O P Q/)
        {
                $node{$_} = Tree::DAG_Node -> new({name => $_});

                $node{$_} -> attributes({uid => ++$count});

        }

        $tree -> add_daughter($node{H});
        $node{H} -> add_daughter($node{I});
        $node{I} -> add_daughter($node{J});
        $node{H} -> add_daughter($node{K});
        $node{H} -> add_daughter($node{L});
        $tree -> add_daughter($node{M});
        $tree -> add_daughter($node{N});
        $node{N} -> add_daughter($node{O});
        $node{O} -> add_daughter($node{P});
        $node{P} -> add_daughter($node{Q});

        print map("$_\n", @{$tree -> tree2string});
        print map("$_\n", @{$tree -> tree2string({no_attributes => 1})});

} # End of tree_dag_node.