    # File lib/active_record/observer.rb, line 113
        def initialize
          observed_classes = [ observed_class ].flatten
          observed_subclasses_class = observed_classes.collect {|c| c.send(:subclasses) }.flatten!
          (observed_classes + observed_subclasses_class).each do |klass|
            klass.add_observer(self)
            klass.send(:define_method, :after_find) unless klass.respond_to?(:after_find)
          end
        end