d(text='CHINA UNICOM').click()出现TypeError: string indices must be integers

最近在做android测试，用到uiautomator，使用d(text='CHINA UNICOM').click()，总是出现：

    d(text='CHINA UNICOM').click()
  File "C:\Program Files\Python37\lib\site-packages\uiautomator\__init__.py", line 76, in __call__
    return self.func(*args, **kwargs)
  File "C:\Program Files\Python37\lib\site-packages\uiautomator\__init__.py", line 971, in _click
    return self.jsonrpc.click(self.selector)
  File "C:\Program Files\Python37\lib\site-packages\uiautomator\__init__.py", line 438, in wrapper
    return _method_obj(*args, **kwargs)
  File "C:\Program Files\Python37\lib\site-packages\uiautomator\__init__.py", line 135, in __call__
    "%s: %s" % (jsonresult["error"]["data"]["exceptionTypeName"], jsonresult["error"]["message"])
TypeError: string indices must be integers

WTF！！！

没找到能不能元素好好报个错误？？

使用SDK工具uiautomatorviewer.bat截取数据查看元素的text名，发现是China Unicom，屏幕上显示的全部大写，元素为开头大写，改过之后可以正常运行