# File lib_wpm/wpm.rb, line 63
    def [](*args)
      case (args.length)
      when 1
        ns_uri, name = '', *args
      when 2
        ns_uri, name = args
      else
        raise 'invalid arguments: ' + args.map{|a| a.inspect }.join(', ')
      end

      if (@map.include? ns_uri) then
        if (@map[ns_uri].include? name) then
          return @map[ns_uri][name][:value]
        end
      end

      nil
    end