old_contents: """
   Simple DHCP Server
  """
  import logging
  
  from ryu.base import app_manager
  from ryu.lib.packet import dchp
  
  class DHCPServer():
      @set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER)
      def _packet_in_handler(self, ev):
          msg = ev.msg
          datapath = msg.datapath
          ofproto = datapath.ofproto
  
          pkt = packet.Packet(msg.data)
          dhcpPacket = pkt.get_protocol(dhcp.dhcp)
          self.logger.info("dchp...%s", dhcpPacket)
   
          if dhcpPacket:
             pass
  
      def handle_dhcp_request(self):
  
      def handle_dhcp_offer(self):
  
      def handle_dhcp_ack(self):  
  
new_contents: """
   Simple DHCP Server
  """
  import logging
  
  from ryu.base import app_manager
  from ryu.lib.packet import dhcp
  from ryu.lib.packet import ipv4
  from ryu.controller.handler import set_ev_cls
  from ryu.controller import ofp_event
  from ryu.controller.handler import MAIN_DISPATCHER
  from ryu.lib.packet import packet
  
  class DHCPServer(app_manager.RyuApp):
      @set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER)
      def _packet_in_handler(self, ev):
          msg = ev.msg
          datapath = msg.datapath
          ofproto = datapath.ofproto
  
          pkt = packet.Packet(msg.data)
          #self.logger.info("pkt...%s", pkt)
          dhcpPacket = pkt.get_protocol(dhcp.dhcp)
          self.logger.info("dhcp...%s", dhcpPacket)
  
          if dhcpPacket:
             pass
  
      def handle_dhcp_request(self):
          pass
  
      def handle_dhcp_offer(self):
          pass
  
      def handle_dhcp_ack(self):
          pass
  
subject: Update simple_dhcp_server.py