code: def return_socket(self, sock_info):
          
          if self.pid != os.getpid():
              self.reset()
          else:
              if sock_info.pool_id != self.pool_id:
                  sock_info.close()
              elif not sock_info.closed:
                  sock_info.last_checkin = _time()
                  with self.lock:
                      self.sockets.add(sock_info)
  
          self._socket_semaphore.release()
          with self.lock:
              self.active_sockets -= 1
docs: Return the socket to the pool, or if it's closed discard it.