    # File lib/chef/resource.rb, line 34
          def duplicates?(other_notification)
            unless other_notification.respond_to?(:resource) && other_notification.respond_to?(:action)
              msg = "only duck-types of Chef::Resource::Notification can be checked for duplication "\
                    "you gave #{other_notification.inspect}"
              raise ArgumentError, msg
            end
            other_notification.resource == resource && other_notification.action == action
          end