def display_messages
      [:errors, :warnings].each do |type|
        send(type).each do |msg|
          output.puts(msg.to_s)
        end
      end
    end
def display_messages
      [:errors, :warnings].each do |type|
        send(type).each do |msg|
          output.puts(msg.to_s)
        end
      end
    end
Displays all warnings and errors.