code: def handleOACK(self, pkt):
          
          if len(pkt.options.keys()) > 0:
              if pkt.match_options(self.context.options):
                  log.info("Successful negotiation of options")
                  # Set options to OACK options
                  self.context.options = pkt.options
                  for key in self.context.options:
                      log.info("    %s = %s" % (key, self.context.options[key]))
              else:
                  log.error("Failed to negotiate options")
                  raise TftpException("Failed to negotiate options")
          else:
              raise TftpException("No options found in OACK")
docs: This method handles an OACK from the server, syncing any accepted
          options.