安装了最新版的appium3.0.0和selenium的最新版本，导致版本冲突从而导致报错：AttributeError: 'NoneType' object has no attribute 'to_capabilities'
解决方案：
卸载selenium和appium，下载低版本的appium【下载appium的同时会下载依赖selenium】
pip install appium-python-client==2.0 -i https://pypi.tuna.tsinghua.edu.cn/simple
- to_capabilities AttributeError capabilities attribute NoneTypeto_capabilities attributeerror capabilities 39 attributeerror attribute nonetype attributeerror containers attribute nonetype to_capabilities 39 attribute nonetype children 39 attribute nonetype object 39 quot attributeerror attribute 39 attributeerror antialias attribute 39 attributeerror tensorflow attribute 39 attributeerror attribute copy_src