# File lib/logging/logger.rb, line 328
    def add_appenders( *args )
      args.flatten.each do |arg|
        o = arg.kind_of?(::Logging::Appender) ? arg : ::Logging::Appenders[arg.to_s]
        raise ArgumentError, "unknown appender #{arg.inspect}" if o.nil?
        @appenders << o unless @appenders.include?(o)
      end
      self
    end