def METHOD_NAME(self):
    """
    Guard method to checks if INBOUND_EMAIL settings present.
    Returns InternalServerError if not.
    """
    # TODO: These settings should be checked before app start.
    if not live_settings.INBOUND_EMAIL_ESP:
        logger.error("InboundEmailWebhookView: INBOUND_EMAIL_ESP env variable must be set.")
        return HttpResponse(
            status=status.HTTP_500_INTERNAL_SERVER_ERROR,
        )
    if not live_settings.INBOUND_EMAIL_DOMAIN:
        logger.error("InboundEmailWebhookView: INBOUND_EMAIL_DOMAIN env variable must be set.")
        return HttpResponse(status=status.HTTP_500_INTERNAL_SERVER_ERROR)