class_docstr: Locking mechanism that issues tickets managing access to conversation IDs.
  
  Tickets are issued in the order in which they are requested. A detailed
  explanation of the ticket lock algorithm can be found at
  http://pages.cs.wisc.edu/~remzi/OSTEP/threads-locks.pdf#page=13
docstr: Return number of the ticket that was last added.
  
  Returns:
       Number of `Ticket` that was last added. `NO_TICKET_ISSUED` if no
       tickets exist.
docstr_tok: ["Return","number","of","the","ticket","that","was","last","added",".","Returns",":","Number","of","`","Ticket","`","that","was","last","added",".","`","NO_TICKET_ISSUED","`","if","no","tickets","exist","."]
code: def last_issued(self) -> int:
      """Return number of the ticket that was last added.
  
      Returns:
           Number of `Ticket` that was last added. `NO_TICKET_ISSUED` if no
           tickets exist.
      """
      ticket_number = self._ticket_number_for(-1)
  
      return (
          ticket_number
          if ticket_number is not None
          else NO_TICKET_ISSUED
      )
  
imports: import json
  import logging
  from collections import deque
  import time
  from typing import Text, Optional, Union, Deque, Dict, Any
label_desc: Use image node_id 7 for calling the TicketLock obj's underlying member method code with example usage: obj.last_issued() and returns: unknown