code: def start(self, *args, **kw):
          
          pid = None
          if os.path.exists(self.pidfile):
              with open(self.pidfile, 'r') as fp:
                  pid = int(fp.read().strip())
  
          if pid:
              msg = 'pidfile (%s) exists. Daemon already running?\n'
              sys.stderr.write(msg % self.pidfile)
              sys.exit(1)
  
          self.daemonize()
          self.run(*args, **kw)
docs: Start the daemon.