[python-3.11] open() - invalid mode 'rU'

[dreamcat4]

Things have changed in the latest python 3 release (3.11)...

[!] Something went wrong while reading firefox profiles.ini
ERROR:root:Traceback (most recent call last):
  File "/home/id/.builds/firefox/ExtAnalysis/core/localextensions.py", line 179, in firefox
    with open(firefox_profile, 'rU') as ini_source:
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
ValueError: invalid mode: 'rU'

Here is some discussion about it Cantera/cantera#1325

[dreamcat4]

The suggested solution seems to be:

Stop using deprecated flag U.... (Quote from stack*):

Since the 'rU' file read-mode is deprecated in python3 so you have to update that code to this. (Change rU to r)