def get_text path = nil
      rv = nil
      if path
        element = @elements[ path ]
        rv = element.get_text unless element.nil?
      else
        rv = @children.find { |node| node.kind_of? Text }
      end
      return rv
    end
def get_text path = nil
      rv = nil
      if path
        element = @elements[ path ]
        rv = element.get_text unless element.nil?
      else
        rv = @children.find { |node| node.kind_of? Text }
      end
      return rv
    end
Returns the first child Text node, if any, or +nil+ otherwise.
 This method returns the actual +Text+ node, rather than the String content.
  doc = Document.new "<p>some text <b>this is bold!</b> more text</p>"
  # The element 'p' has two text elements, "some text " and " more text".
  doc.root.get_text.value            #-> "some text "