code: def start(self):
          
          # Check for a pidfile to see if the daemon already runs
          try:
              pf = file(self.pidfile, 'r')
              pid = int(pf.read().strip())
              pf.close()
              os.kill(pid, 0)
          except IOError:
              pid = None
          except OSError:
              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
          self._daemonize()
docs: Start the daemon