# File lib/active_support/callbacks.rb, line 596
      def define_callbacks(*callbacks)
        config = callbacks.last.is_a?(Hash) ? callbacks.pop : {}
        callbacks.each do |callback|
          extlib_inheritable_reader("_#{callback}_callbacks") do
            CallbackChain.new(callback, config)
          end
          __define_runner(callback)
        end
      end