def switch_lang(self, language):
if not language or not self.locale_dirs:
translator = NullTranslations()
else:
# Instantiate the whole translator chain
translator = None
for locale_dir in self.locale_dirs:
_translator = get_package_translator(language,
locale_dir=locale_dir)
if translator is None:
translator = _translator # Head of chain
else:
translator.add_fallback(_translator)
self.ugettext = translator.gettext
self.language = language
# update all the kv rules attached to this text
_obsolete_idx = []
for idx, (func, largs, kwargs) in enumerate(self.observers):
try:
func(largs, None, None)
except ReferenceError:
_obsolete_idx.append(idx)
for _idx in reversed(_obsolete_idx):
# Reversed loop, to preserve meaning of indexes
del self.observers[_idx]
