python操作pdf的库

import pdf2docx
import PyPDF2
import spire

参考：
https://chuna2.787528.xyz/geekbruce/articles/18427413
https://cloud.tencent.cn/developer/article/2573206
https://blog.csdn.net/engchina/article/details/149240467
https://zhuanlan.zhihu.com/p/352722932
https://blog.csdn.net/weixin_42321517/article/details/139337170