code: def valid_host_with_port(hostport):
      
      host, port = hostport.rsplit(":", 1) if ":" in hostport else (hostport, None)
  
      # first, validate host or IP
      if not valid_ipv4(host) and not valid_host(host):
          return False
  
      # now, validate port
      if port is not None and not valid_port(port):
          return False
  
      return True
docs: matches hostname or an IP, optionally with a port