Fields deleted/cleared when calling update_page_form_field_values

[neversphere]

I'm trying to automatically populate/update fields in a PDF but when I call update_page_form_field_values some of the fields in the form are cleared. If I just read the pdf and write it without calling update_page_form_field_values the fields show up when the PDF is rendered. These fields are also cleared if I call writer.set_need_appearances_writer() without calling update_page_form_field_values.

Original PDF: https://drive.google.com/file/d/1QRlVzVmB63xwN-Ybm-sEhyozenCBBn6q/view?usp=sharing

PDF just read and written: https://drive.google.com/file/d/1fJhod2UnneXegunQocR_cPs5TCnekwRh/view?usp=sharing

PDF post update_page_form_field_valuess: https://drive.google.com/file/d/1PutoaB1YLJNfk9_kfuXfRmRQSb7Ka2hp/view?usp=sharing

The following fields are clear after the empty dict is used for the update_page_form_field_values:

21A
21E
32
33

These fields are also cleared if a populated dict is used to update other fields.

---

Current code to update:

import sys, getopt
from pypdf import PdfReader, PdfWriter

argv = sys.argv[1:]

reader = PdfReader(argv[0])
writer = PdfWriter()

page = reader.pages[0]
writer.add_page(page)

with open(argv[0]+'-no-change.pdf', "wb") as output_stream:
    writer.write(output_stream)

writer.update_page_form_field_values(
    writer.pages[0], {}
)

with open(argv[0]+'-empty-dict-change.pdf', "wb") as output_stream:
    writer.write(output_stream)

[neversphere]

This was a documentation error. Updated with #1806