private void deleteProxyGrantingTicketFromParent(final ProxyGrantingTicket ticket) throws Exception {
        if (ticket.getTicketGrantingTicket() instanceof final TicketGrantingTicket tgt) {
            tgt.getProxyGrantingTickets().remove(ticket.getId());
            updateTicket(tgt);
        }
    }
Delete ticket-granting ticket's service tickets.

@param ticket the ticket
@return the count of tickets that were removed including child tickets and zero if the ticket was not deleted
core/cas-server-core-tickets-api/src/main/java/org/apereo/cas/ticket/registry/AbstractTicketRegistry.java