# File temp/parent.rb, line 82
    def insert_before( child1, child2 )
      if child1.kind_of? String
        child1 = XPath.first( self, child1 )
        child1.parent.insert_before child1, child2
      else
        ind = index(child1)
        child2.parent.delete(child2) if child2.parent
        @children[ind,0] = child2
        child2.parent = self
      end
      self
    end