# File lib/state_machine/integrations/active_record.rb, line 412
        def add_callback(type, options, &block)
          options[:terminator] = @terminator ||= lambda {|result| result == false}
          @callbacks[type].insert(-2, callback = Callback.new(options, &block))
          add_states(callback.known_states)
          
          callback
        end