It's to add ToC(outline/bookmark) to pdf files. The file is from https://github.com/Igalia/intel-osrc-gfx-prm.git. To simplify the case, the file path is put to a list. Just run ` python3 upt_toc.py` to update the ToC. It generated the 'ToC', but they are not recognized by default App in Mac and PDF Expert in ios11.