public ExpirationPolicy toServiceTicketExpirationPolicy() {
        val st = casProperties.getTicket().getSt();
        val timeToKillInSeconds = Beans.newDuration(st.getTimeToKillInSeconds()).toSeconds();
        return new MultiTimeUseOrTimeoutExpirationPolicy.ServiceTicketExpirationPolicy(st.getNumberOfUses(), timeToKillInSeconds);
    }
To service ticket expiration policy.

@return the expiration policy
core/cas-server-core-tickets-api/src/main/java/org/apereo/cas/ticket/expiration/builder/ServiceTicketExpirationPolicyBuilder.java