ERROR: Could not install packages due to an EnvironmentError: [WinError 5]

Python 安装库出现以下错误:
ERROR: Could not install packages due to an EnvironmentError: [WinError 5] 拒绝访问。: ‘C:\anocoda\Lib\site-packages\cv2\cv2.cp37-win_amd64.pyd’

解决方法:在安装命令后面加 --user
pip install opencv_contrib_python==3.4.2.16 --user
ERROR: Could not install packages due to an EnvironmentError: [WinError 5]