GNU gettext: Print string translated and untranslated at the same time

[c.buhtz at posteo.jp]

X-Post: https://stackoverflow.com/q/76913082/4865723

I want to display one string in its original source (untranslated) 
version and in its translated version site by site without duplicating 
the string in the python source code?
It wouldn't be a big deal if it is only one word.

     print('The translated string "{}" is originally 
"{}".'.format(_('Hello'), 'Hello'))

But in my situation it is a multi line string containing multiple 
paragraphs. It is a full text. I don't want to duplicate that string.

     # Imagine 'Hello' as a 50x70 characters multi line string.
     original = 'Hello'
     translated = _('Hello')
     print('The translated string "{}" is originally 
"{}".'.format(translated, original))

I do use the "class based API" of GNU gettext. My current approach, 
which is not working, is to somehow (how!?) disable (or mask) the 
translation function "_()" temporarily.
But as described in the stackoverflow question (see first line of this 
mail) this do not work.

def foobar(translate):
     if not translate:
         # I try to mask the global _() builtins-function
         def _(txt):
             return txt

     return _('Hello')

if __name__ == '__main__':

     # To ilustrate that _() is part of "builtins" namespace
     print(_('No problem.'))

     print('The translated string "{}" is originally "{}".'
           .format(foobar(True), foobar(False)))

This is the output:

     Traceback (most recent call last):
       File "/home/user/ownCloud/_transfer/./z.py", line 27, in <module>
         .format(foobar(True), foobar(False)))
       File "/home/user/ownCloud/_transfer/./z.py", line 19, in foobar
         return _('Hello')
     UnboundLocalError: local variable '_' referenced before assignment

The full MWE can be found at stackoverflow 
(https://stackoverflow.com/q/76913082/4865723).

The question is if this can be solved somehow or if there is an 
alternative approach.
The "_()" function is installed in the builtins namespace because of 
gettext class based API. This is nice.
Maybe I can somehow manipulate that builtins namespace? I tried to 
import builtins and played around with it but couldn't find a way to do 
it.

Thanks
Christian Buhtz

PS: This is IMHO not relevant for my question but if someone is 
interested the connection to productive code can be found in this issue: 
https://github.com/bit-team/backintime/issues/1473 There I describe what 
I want to achive and also provide a GUI mockup.