class Nokogiri::XML::Builder

def insert(node, &block)

Insert +node+ as a child of the current Node
## 
def insert(node, &block)
  node = @parent.add_child(node)
  if block_given?
    old_parent = @parent
    @parent = node
    @arity ||= block.arity
    if @arity <= 0
      instance_eval(&block)
    else
      block.call(self)
    end
    @parent = old_parent
  end
  NodeBuilder.new(node, self)
end