# File lib/action_controller/metal/mime_responds.rb, line 231
    def respond_with(*resources, &block)
      raise "In order to use respond_with, first you need to declare the formats your " <<
            "controller responds to in the class level" if self.class.mimes_for_respond_to.empty?

      if response = retrieve_response_from_mimes(&block)
        options = resources.size == 1 ? {} : resources.extract_options!
        options.merge!(:default_response => response)
        (options.delete(:responder) || self.class.responder).call(self, resources, options)
      end
    end