# File lib/xml/dom2/node.rb, line 340
      def _insertNodes(index, node)
        if node.nodeType == DOCUMENT_FRAGMENT_NODE

          node.childNodes.to_a.each_with_index do |n, i|
            if index == -1
              _insertNodes(-1, n)
            else
              _insertNodes(index + i, n)
            end
          end
        elsif node.is_a?(Node)
          ## to be checked
          _checkNode(node)
          node._removeFromTree
          if index == -1
            @children.push(node)
          else
            @children[index, 0] = node
          end
          node.parentNode = self
        else
          raise ArgumentError, "invalid value for Node"
        end
      end