code: protected String handleAbstractTicketException(final AbstractTicketException e, final RequestContext requestContext) {
          val messageContext = requestContext.getMessageContext();
          val match = this.errors.stream()
              .filter(c -> c.isInstance(e)).map(Class::getSimpleName)
              .findFirst();
  
          match.ifPresent(s -> messageContext.addMessage(new MessageBuilder().error().code(e.getCode()).build()));
          return match.orElse(UNKNOWN);
      }
docs: Maps an {@link AbstractTicketException} onto a state name equal to the simple class name of the exception with
  highest precedence. Also sets an ERROR severity message in the message context with the error code found in
  {@link AbstractTicketException#getCode()}. If no match is found,
  {@value #UNKNOWN} is returned.
  
  @param e              Ticket exception to handle.
  @param requestContext the spring context
  @return Name of next flow state to transition to or {@value #UNKNOWN}