tasks.py

    try:
        doc._move_tree(new_slug, user=user)
    except Exception as e:
        message = """
        Page move failed.

        Move was requested for document with slug %(slug)s in locale %(locale)s,
        but could not be completed. The following error was raised:

        %(info)
        """ % {'slug': slug, 'locale': locale, 'info': e}
        logging.error(message)
        send_mail('Page move failed', message, settings.DEFAULT_FROM_EMAIL,
                  [user.email])