ValueError: invalid literal for int() with base 10: ''

[defarm]

I have a toc file for a textbook but running pdftocio linear_algebra_5th_edition.pdf < toc returns the error in the title. Here's the result with a -g flag:

df@tower:~/pdftocgen$ pdftocio -g linear_algebra_5th_edition.pdf < toc_new
Traceback (most recent call last):
  File "/home/df/.local/bin/pdftocio", line 8, in <module>
    sys.exit(main())
  File "/home/df/.local/lib/python3.10/site-packages/pdftocio/app.py", line 166, in main
    raise e
  File "/home/df/.local/lib/python3.10/site-packages/pdftocio/app.py", line 156, in main
    toc = parse_toc(toc_file)
  File "/home/df/.local/lib/python3.10/site-packages/pdftocio/tocparser.py", line 38, in parse_toc
    return list(map(parse_entry, reader))
  File "/home/df/.local/lib/python3.10/site-packages/pdftocio/tocparser.py", line 22, in parse_entry
    int(entry[indent + 1]),  # pagenum
ValueError: invalid literal for int() with base 10: ''

and here's the toc file.
toc.txt

Thanks in advance!

[Krasjet]

There is no page number for the line

    "6.7* THE SINGULAR VALUE DECOMPOSITION AND THE PSEUDOINVERSE" 

I probably need to add a more friendly error message.