# File /home/cepheus/projects/prep/log4r-1.0.0/src/log4r/outputter.rb, line 136
    def only_at(*levels)
      raise ArgumentError, "Gimme some levels!", caller if levels.empty?
      raise ArgumentError, "Can't log only_at ALL", caller if levels.include? ALL
      levels.each {|level| Log4rTools.validate_level(level)}
      @level = levels.sort.first
      OutputterFactory.create_methods self, levels
    end