error reading fillable pdf

[lylia0009]

I am trying to update a fillable PFD form with python, when trying to read it it throws an exception. Below are the code, sample pdf and the error thrown. Is there any one seen this before?

import pdfrw
pdf = pdfrw.PdfReader(input_pdf)
Error message

~\Anaconda3\lib\site-packages\pdfrw\pdfreader.py in init(self, fname, fdata, decompress, decrypt, password, disable_gc, verbose)
648
649 if is_stream:
--> 650 self.load_stream_objects(trailer.object_streams)
651
652 while xref_list:

~\Anaconda3\lib\site-packages\pdfrw\pdfreader.py in load_stream_objects(self, object_streams)
306 firstoffset = int(obj.First)
307 while objsource.floc < firstoffset:
--> 308 offsets.append((int(next()), firstoffset + int(next())))
309 for num, offset in offsets:
310 # Read the object, and call special code if it starts

ValueError: invalid literal for int() with base 10: "ÔÞíWÎ0vætºUÐ\x8a\x13õ#v\x9f0uÀ\x08C5n¡³ñų\x9d\x93\x91\x06Åo\x11j\x8eO8êøÏ\x96\x1fá?\x10ãoÂõõÀù,,1!6HêíG\x1eb\x18½'éïz²å½#¸,\x9e"```

Sample pdf
https://www.uobgroup.com/hk/assets/pdfs/Billof-Exchange.pdf