old_contents: from .utils import option
  
  
  class ImproperlyConfigured(Exception):
      pass
  
  
  class UnknownLocaleError(Exception):
      def __init__(self, locale, obj):
          Exception.__init__(self,
              'Unknown locale %s given. Locale is not one of %r' % (
                  locale, list(option(obj, 'locales'))
              )
          )
  
new_contents: from .utils import option
  
  
  class ImproperlyConfigured(Exception):
      pass
  
  
  class UnknownLocaleError(Exception):
      def __init__(self, locale, obj):
          Exception.__init__(self,
              'Unknown locale %s given for %r. Locale is not one of %r' % (
                  locale, obj, list(option(obj, 'locales'))
              )
          )
  
subject: Add better error msg