<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _add_app_menu(self):
 """ Create a default Cocoa menu that shows 'Services', 'Hide', 'Hide Others', 'Show All', and 'Quit'. Will append the application name to some menu items if it's available. """

        # Set the main menu for the application
        mainMenu = AppKit.NSMenu.alloc().init()
        self.app.setMainMenu_(mainMenu)

        # Create an application menu and make it a submenu of the main menu
        mainAppMenuItem = AppKit.NSMenuItem.alloc().init()
        mainMenu.addItem_(mainAppMenuItem)
        appMenu = AppKit.NSMenu.alloc().init()
        mainAppMenuItem.setSubmenu_(appMenu)

        appMenu.addItemWithTitle_action_keyEquivalent_(self._append_app_name(localization["cocoa.menu.about"]), "orderFrontStandardAboutPanel:", "")

        appMenu.addItem_(AppKit.NSMenuItem.separatorItem())

        # Set the 'Services' menu for the app and create an app menu item
        appServicesMenu = AppKit.NSMenu.alloc().init()
        self.app.setServicesMenu_(appServicesMenu)
        servicesMenuItem = appMenu.addItemWithTitle_action_keyEquivalent_(localization["cocoa.menu.services"], nil, "")
        servicesMenuItem.setSubmenu_(appServicesMenu)

        appMenu.addItem_(AppKit.NSMenuItem.separatorItem())

        # Append the 'Hide', 'Hide Others', and 'Show All' menu items
        appMenu.addItemWithTitle_action_keyEquivalent_(self._append_app_name(localization["cocoa.menu.hide"]), "hide:", "h")
        hideOthersMenuItem = appMenu.addItemWithTitle_action_keyEquivalent_(localization["cocoa.menu.hideOthers"], "hideOtherApplications:", "h")
        hideOthersMenuItem.setKeyEquivalentModifierMask_(AppKit.NSAlternateKeyMask | AppKit.NSCommandKeyMask)
        appMenu.addItemWithTitle_action_keyEquivalent_(localization["cocoa.menu.showAll"], "unhideAllApplications:", "")

        appMenu.addItem_(AppKit.NSMenuItem.separatorItem())

        # Append a 'Quit' menu item
        appMenu.addItemWithTitle_action_keyEquivalent_(self._append_app_name(localization["cocoa.menu.quit"]), "terminate:", "q")