'Merge translations from each installed app.'

def _add_installed_apps_translations(self):

    try:
        app_configs = reversed(list(apps.get_app_configs()))
    except AppRegistryNotReady:
        raise AppRegistryNotReady("The    translation    infrastructure    cannot    be    initialized    before    the    apps    registry    is    ready.    Check    that    you    don't    make    non-lazy    gettext    calls    at    import    time.")
    for app_config in app_configs:
        localedir = os.path.join(app_config.path, 'locale')
        if os.path.exists(localedir):
            translation = self._new_gnu_trans(localedir)
            self.merge(translation)
