How to use the gaiatest.GaiaApps function in gaiatest

def run(self, args=sys.argv[1:]):
        args = self.parser.parse_args()

        host, port = args.address.split(':')
        self.marionette = Marionette(host=host, port=int(port))
        self.marionette.start_session()

        self.apps = gaiatest.GaiaApps(self.marionette)
        self.data_layer = gaiatest.GaiaData(self.marionette)
        self.device = gaiatest.GaiaDevice(self.marionette)

        ret = args.func(args)
        if ret is None:
            ret = 0

        self.marionette.delete_session()

        sys.exit(ret)

def after_connect(self, executor):
        self.executor = executor
        self.marionette = executor.marionette
        self.executor.logger.debug("Running browser.after_connect steps")

        self.gaia_apps = gaiatest.GaiaApps(marionette=executor.marionette)

        self.executor.logger.debug("Waiting for homescreen to load")

        # Moved out of gaia_test temporarily
        self.executor.logger.info("Waiting for B2G to be ready")
        self.wait_for_homescreen(timeout=60)

        self.install_cert_app()
        self.use_cert_app()

def __init__(self, marionette):
        self.marionette = marionette
        self.apps = GaiaApps(self.marionette)
        self.accessibility = Accessibility(self.marionette)
        self.frame = None
        self.entry_point = hasattr(self, 'entry_point') and self.entry_point or None

def install_apps():
        mc = get_marionette(args)
        device = GaiaDevice(mc)
        try:
            device.restart_b2g()
            print 'Your device is rebooting.'
        except Exception:
            print ' ** Check to make sure you don\'t have desktop B2G running'
            raise

        apps = GaiaApps(mc)
        apps.kill_all()

        lockscreen = LockScreen(mc)
        lockscreen.unlock()

        if args.wifi_ssid:
            print 'Configuring WiFi'
            if not args.wifi_key or not args.wifi_pass:
                args.error('Missing --wifi_key or --wifi_pass option')
            args.wifi_key = args.wifi_key.upper()

            data_layer = GaiaData(mc)
            data_layer.enable_wifi()
            if args.wifi_key == 'WPA-PSK':
                pass_key = 'psk'
            elif args.wifi_key == 'WEP':

def kill_all_apps(args):
    mc = get_marionette(args)
    apps = GaiaApps(mc)
    apps.kill_all()
    print 'Killed all apps'

'/mnt/extsdcard',
                         '/storage/sdcard',
                         '/storage/sdcard0',
                         '/storage/sdcard1']:
                if self.device.file_manager.dir_exists(path):
                    for item in self.device.file_manager.list_items(path):
                        self.device.file_manager.remove('/'.join([path, item]))

        self.logger.debug('Populating databases')
        self.populate_databases()

        if self.restart:
            self.logger.debug('Starting B2G')
            self.device.start_b2g(self.start_timeout)

        self.apps = gaiatest.GaiaApps(self.marionette)
        self.data_layer = gaiatest.GaiaData(self.marionette)

        self.logger.debug('Populating files')
        self.populate_files()

        self.logger.debug('Settling for %d seconds' % self.settle_time)
        time.sleep(self.settle_time)

        self.marionette.switch_to_frame()

        safe_volume = 5
        self.logger.debug('Setting content volume to %d' % safe_volume)
        self.data_layer.set_setting('audio.volume.content', safe_volume)

        self.logger.debug('Switching off keyboard first time use screen')
        self.data_layer.set_setting('keyboard.ftu.enabled', False)

print 'App successfully installed.'

    # marketplace loading fragment locator
    _loading_fragment_locator = ('css selector', 'div#splash-overlay')
    _search_locator = ('id', 'search-q')

    if not args.app and not args.manifest and not args.app_url:
        args.error('Provide either app name (using --app), URL of app\'s '
                   'manifest file (using --manifest) or URL of the app '
                   'on marketpalce (using --app_url).')

    mc = get_marionette(args)
    lockscreen = LockScreen(mc)
    lockscreen.unlock()

    apps = GaiaApps(mc)
    apps.kill_all()

    no_internet_error = ('Unable to download app.\nReason: You are probably '
                         'not connected to internet on your device.')

    if args.manifest:
        mc.execute_script('navigator.mozApps.install("%s")' % args.manifest)
        try:
            confirm_installation()
        except TimeoutException, exc:
            print '** %s: %s' % (exc.__class__.__name__, exc)
            args.error(no_internet_error)
        return

    if args.prod:
        marketplace_app = 'Marketplace'

def do_login(args):
    mc = get_marionette(args)
    device = GaiaDevice(mc)
    apps = GaiaApps(mc)
    data_layer = GaiaData(mc)

    _persona_frame_locator = ('css selector', "iframe")

    # Trusty UI on home screen
    _tui_container_locator = ('id', 'trustedui-frame-container')

    # Persona dialog
    _waiting_locator = ('css selector', 'body.waiting')
    _email_input_locator = ('id', 'authentication_email')
    _password_input_locator = ('id', 'authentication_password')
    _new_password = ('id', 'password')
    _verify_new_password = ('id', 'vpassword')
    _next_button_locator = ('css selector', 'button.start')
    _verify_start_button = ('css selector', 'button#verify_user')
    _returning_button_locator = ('css selector', 'button.returning')