Plural translations whe not logged

[trasher]

Running a custom script from command line; we get the following error:

Fatal error: Uncaught Error: Call to a member function translatePlural() on null in /var/www/glpi/inc/autoload.function.php:171
Stack trace:
#0 /var/www/glpi/inc/notepad.class.php(171): _n('Note', 'Notes', 2)
#1 /var/www/glpi/inc/computer.class.php(881): Notepad::getSearchOptionsToAdd()
#2 /var/www/glpi/inc/search.class.php(5382): Computer->getSearchOptions()
#3 /var/www/glpi/inc/log.class.php(124): Search::getOptions('Computer')
#4 /var/www/glpi/inc/commondbtm.class.php(381): Log::constructHistory(Object(Infocom), Array, Array)
#5 /var/www/glpi/inc/commondbtm.class.php(1146): CommonDBTM->updateInDB(Array, Array)
#6 /path/to/scrpit.php(1234): CommonDBTM->update(Array)
#7 {main}
  thrown in /var/www/glpi/inc/autoload.function.php on line 171

Problem is $TRANSLATION variable is only set once logged in. There is a fallback for the __() method, but not for _n().