code: def start(self):
          
          # Check for a pidfile to see if the daemon already runs
          logger.info('Starting daemon')
          try:
              with open(self.pidfile, 'r') as fd:
                  pid = int(fd.read().strip())
          except IOError:
              pid = None
  
          if pid:
              message = "pidfile %s already exist. Daemon already running?\n"
              sys.stderr.write(message % self.pidfile)
              sys.exit(1)
  
          # Start the daemon
          pid = self.daemonize()
          if pid:
              return pid
          self.run()
docs: Start the daemon