code: def buy_streak_freeze(self):
          
          lang = self.get_abbreviation_of(self.get_user_info()['learning_language_string'])
          if lang is None:
              raise Exception('No learning language found')
          try:
              self.buy_item('streak_freeze', lang)
              return True
          except AlreadyHaveStoreItemException:
              return False
docs: figure out the users current learning language
          use this one as parameter for the shop