code: def serve(self, port=None, address=None):
          
          port = port or self.port
          address = address or self.address
  
          log.info('Starting SMTP server at {0}:{1}'.format(address, port))
  
          server = InboxServer(self.collator, (address, port), None)
  
          try:
              asyncore.loop()
          except KeyboardInterrupt:
              log.info('Cleaning up')
docs: Serves the SMTP server on the given port and address.