【经验教训】解决下载了opencv-python-headless但import cv2失败的问题

问题原因：即使曾经下载过 opencv-python 已经卸载也不行

解决办法：下载 opencv-python-headless 时使用 python.exe -m pip install opencv-python-headless

参考链接：Installed opencv-python but cannot import (ModuleNotFoundError: No module named 'cv2') - Stack Overflow