code: def is_present(self, host=None):
          
          r = self.local_renderer
          r.env.host = host or self.genv.host_string
          ret = r._local("getent hosts {host} | awk '{{ print $1 }}'", capture=True) or ''
          if self.verbose:
              print('ret:', ret)
          ret = ret.strip()
          if self.verbose:
              print('Host %s %s present.' % (r.env.host, 'IS' if bool(ret) else 'IS NOT'))
          ip = ret
          ret = bool(ret)
          if not ret:
              return False
  
          r.env.ip = ip
          with settings(warn_only=True):
              ret = r._local('ping -c 1 {ip}', capture=True) or ''
          packet_loss = re.findall(r'([0-9]+)% packet loss', ret)
  #         print('packet_loss:',packet_loss)
          ip_accessible = packet_loss and int(packet_loss[0]) < 100
          if self.verbose:
              print('IP %s accessible: %s' % (ip, ip_accessible))
          return bool(ip_accessible)
docs: Returns true if the given host exists on the network.
          Returns false otherwise.