# File lib/openurl/transport.rb, line 125
    def merge_context_objects
      ctx_doc = REXML::Document.new(@context_objects[0].xml)
      root = ctx_doc.root
      @context_objects.each do | ctx |
        next if @context_objects.index(ctx) == 0
        c_doc = REXML::Document.new(ctx.xml)
        c_elm = c_doc.elements['ctx:context-objects/ctx:context-object']
        root.add_element(c_elm)
      end      
      return ctx_doc.to_s
    end