每次我运行蜘蛛时，以下信息会首先出现在所有其他信息之前。
`:0: 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.
现在我下载service_identity-18.1.0-py2.py3-none-any.whl并安装它。
pip3 freeze |grep identity
service-identity==18.1.0
再次运行蜘蛛，我仍然收到警告信息'cannot import name 'opentype'，我的抓狂是怎么回事？
sudo pip3 install service-identity
Requirement already satisfied: service-identity in /usr/local/lib/python3.5/dist-packages (18.1.0)
Requirement already satisfied: cryptography in /usr/lib/python3/dist-packages (from service-identity) (1.7.1)
Requirement already satisfied: pyasn1 in /usr/lib/python3/dist-packages (from service-identity) (0.1.9)
Requirement already satisfied: attrs>=16.0.0 in /usr/local/lib/python3.5/dist-packages (from service-identity) (19.1.0)
Requirement already satisfied: pyasn1-modules in /usr/local/lib/python3.5/dist-packages (from service-identity) (0.2.5)