isolate_namespace

# File railties/lib/rails/engine.rb, line 384
      def isolate_namespace(mod)
        engine_name(generate_railtie_name(mod.name))

        routes.default_scope = { module: ActiveSupport::Inflector.underscore(mod.name) }
        self.isolated = true

        unless mod.respond_to?(:railtie_namespace)
          name, railtie = engine_name, self

          mod.singleton_class.instance_eval do
            define_method(:railtie_namespace) { railtie }

            unless mod.respond_to?(:table_name_prefix)
              define_method(:table_name_prefix) { "#{name}_" }
            end

            unless mod.respond_to?(:use_relative_model_naming?)
              class_eval "def use_relative_model_naming?; true; end", __FILE__, __LINE__
            end

            unless mod.respond_to?(:railtie_helpers_paths)
              define_method(:railtie_helpers_paths) { railtie.helpers_paths }
            end

            unless mod.respond_to?(:railtie_routes_url_helpers)
              define_method(:railtie_routes_url_helpers) { |include_path_helpers = true| railtie.routes.url_helpers(include_path_helpers) }
            end
          end
        end
      end

      # Finds engine with given path.
      def find(path)
        expanded_path = File.expand_path path
        Rails::Engine.subclasses.each do |klass|
          engine = klass.instance
          return engine if File.expand_path(engine.root) == expanded_path
        end
        nil
      end
    end