本文针对是Python3的环境遇到的问题，如果是Python2，卸载以及安装相应的pyqt4版本。
遇到问题：
?第一步：删除原有的pyqt
pip uninstall pyqt5
pip uninstall pyqt5-sip?第二步：重新安装pyqt
由于第一次安装pyqt，出现这个错误
ERROR: pip's dependency resolver does not currently take into account all the packages that are installed. This behaviour is the source of the following dependency conflicts.
spyder 5.0.4 requires pyqtwebengine<5.13, which is not installed.
spyder 5.0.4 requires pyqt5<5.13, but you have pyqt5 5.13.0 which is incompatible.
所以需要下载对应版本：
pip install PyQt5-5.12.3-5.12.10-cp35.cp36.cp37.cp38.cp39-none-win_amd64.whl
pip install PyQtWebEngine-5.12.1-5.12.10-cp35.cp36.cp37.cp38.cp39-none-win_amd64.whl
下载链接：