docs: def off(self):
          """!
          \~english
          Close Audio output. set pin mode to output
          @return a boolean value. if True means close audio output is OK otherwise failed to close.
  
          \~chinese
          关闭音频输出。 将引脚模式设置为输出
          @return 布尔值。 如果为 True 关闭音频输出成功，否则关闭不成功。
          """
          isOK = True
          try:
              if self.channelR!=None:
                  sub.call(["gpio","-g","mode", "{}".format(self.channelR), self.PIN_MODE_OUTPUT ])
          except:
              isOK = False
              print("Close audio right channel failed.")
  
          try:
              if self.channelL!=None:
                  sub.call(["gpio","-g","mode", "{}".format(self.channelL), self.PIN_MODE_OUTPUT ])
          except:
              isOK = False
              print("Close audio left channel failed.")
          return isOK