docs: def pid(self, pidnum):
          """Set the pid for a running process."""
          try:
  
              with open(self.pidfile, "w+") as pidfile:
  
                  pidfile.write("{0}\n".format(pidnum))
  
          except IOError:
  
              LOG.exception("Failed to write pidfile {0}).".format(self.pidfile))
              sys.exit(exit.PIDFILE_INACCESSIBLE)