由于初始化时要使用 appium 的键盘，所以设置了 desired_caps['unicodeKeyboard'] = True。然后就要在 teardown 中重设原来的输入法，但是当我使用了 desired_caps['automationName'] = 'uiautomator2'这个设置之后，每次执行 teardown 时，都无法重设输入法。。。。这是怎么一回事呢？？？有什么解决办法么？？？
代码如下：

@classmethod
    def setUpClass(self):
        print("setup begin")
        desired_caps = {}
        desired_caps['platformName'] = 'Android'
        desired_caps['deviceName'] = DeviceName        
        desired_caps['platformVersion'] = PlatformVersion        

        desired_caps['appPackage'] = 'com.xxxxx'
        desired_caps['appActivity'] = 'com.xxxxy'
        desired_caps['noReset'] = True#无需每次都重新安装apk

        #desired_caps['automationName']='selendroid'
        desired_caps['automationName'] = 'uiautomator2'#据说这样就可以用xpath查找了？
        #写了上面这句，在查看driver.available_ime_engines的时候就会出错，原因未知

        desired_caps['unicodeKeyboard'] = True#设置使用appium的Unicode键盘
        desired_caps["resetKeyBoard"]=True#该设置被appium忽略了，无用

        global driver

        driver = webdriver.Remote('http://localhost:4723/wd/hub', desired_caps)
        #self.driver

        print("setup over!")

    @classmethod
    def tearDownClass(self):  
        #driver = self.driver          
        print("teardown")
        a= driver.available_ime_engines
        print(a)
        #重设输入法
        driver.activate_ime_engine(a[0])#'com.iflytek.inputmethod/.FlyIME'
        driver.quit()

出错信息如下：
Traceback (most recent call last):
File "E:\workspace\Pythonlearn1\src\salon\setUrl.py", line 57, in tearDownClass
a= driver.available_ime_engines
File "G:\Python36\lib\site-packages\appium\webdriver\webdriver.py", line 683, in available_ime_engines
return self.execute(Command.GET_AVAILABLE_IME_ENGINES, {})['value']
File "G:\Python36\lib\site-packages\selenium\webdriver\remote\webdriver.py", line 256, in execute
self.error_handler.check_response(response)
File "G:\Python36\lib\site-packages\appium\webdriver\errorhandler.py", line 29, in check_response
raise wde
File "G:\Python36\lib\site-packages\appium\webdriver\errorhandler.py", line 24, in check_response
super(MobileErrorHandler, self).check_response(response)
File "G:\Python36\lib\site-packages\selenium\webdriver\remote\errorhandler.py", line 194, in check_response
raise exception_class(message, screen, stacktrace)
selenium.common.exceptions.WebDriverException: Message: An unknown server-side error occurred while processing the command. Original error: Could not proxy. Proxy error: Could not proxy command to remote server. Original error: 404 - ""

求支招~~