UnicodeDecodeError in cups.py in getSystemPPDs

[Jm]

HPLIP 3.21.4 installation failed at step "POST-BUILD COMMANDS" with the error below.

My OS: Ubuntu 20.04 / python3

# sh ./hplip-3.21.4.run

POST-BUILD COMMANDS
-------------------
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xfa in position 1: invalid start byte

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "./install.py", line 241, in <module>
    text_install.start(language, auto, test_depends, test_unknown, assume_network, max_retries, enable, disable)
  File "/tmp/hplip-3.21.4/installer/text_install.py", line 1424, in start
    cups.getSystemPPDs()
  File "/tmp/hplip-3.21.4/prnt/cups.py", line 339, in getSystemPPDs
    ppd_dict = cupsext.getPPDList()
SystemError: <built-in function getPPDList> returned a result with an error set

Probably similar to https://bugs.launchpad.net/hplip/+bug/1895153/comments/2