重启过电脑 OK,但跑几次脚本后又出现断开的情况了，哪位大神帮帮忙，代码是没有问题的

Traceback (most recent call last):
  File "C:\Users\gionee\Desktop\1.py", line 22, in setUp
    self.driver = webdriver.Remote("http://127.0.0.1:4723/wd/hub", desired_caps)
  File "build\bdist.win-amd64\egg\appium\webdriver\webdriver.py", line 35, in __init__
    super(WebDriver, self).__init__(command_executor, desired_capabilities, browser_profile, proxy, keep_alive)
  File "C:\Python27\lib\site-packages\selenium\webdriver\remote\webdriver.py", line 73, in __init__
    self.start_session(desired_capabilities, browser_profile)
  File "C:\Python27\lib\site-packages\selenium\webdriver\remote\webdriver.py", line 121, in start_session
    'desiredCapabilities': desired_capabilities,
  File "C:\Python27\lib\site-packages\selenium\webdriver\remote\webdriver.py", line 173, in execute
    self.error_handler.check_response(response)
  File "C:\Python27\lib\site-packages\selenium\webdriver\remote\errorhandler.py", line 164, in check_response
    raise exception_class(message, screen, stacktrace)
WebDriverException: Message: u'A new session could not be created. (Original error: Could not find a connected Android device.)'