问题
UserWarning: You do not have a working installation of the service_identity module: 'cannot import name 'opentype''. Please install it from <https://pypi.python.org/pypi/service_identity> and make sure all of its dependencies are satisfied. Without the service_identity module, Twisted can perform only rudimentary TLS client hostname verification. Many valid certificate/hostname mappings may be rejected.
分析问题
分析问题原因：
Please install it from <https://pypi.python.org/pypi/service_identity> and make sure all of its dependencies are satisfied.
故需要在网站下载service_identity的whl组件：https://pypi.python.org/pypi/service_identity
接下来进行安装：
sudo pip3 install service_identity-17.0.0-py2.py3-none-any.whl
又出现还未解决的一些问题：
针对这个问题，主要是一些安装包的版本不一致导致的，可直接强制更新，输入以下命令：
sudo pip3 install service_identity --force --upgrade