def error403(error):
    """
    Custom 403 page.
    """
    tb = error.traceback

    if isinstance(tb, dict) and "name" in tb and "uuid" in tb:
        return SimpleTemplate(PRIVATE_ACCESS_MSG).render(
            name=error.traceback["name"],
            uuid=error.traceback["uuid"]
        )

    return "Access denied!"
Custom 403 page.