anchor.diff:  
         portNumber = mkOption {
           default = 22;
  +        type = types.port;
           description = ''
             The port on which to listen for connections.
           '';
  
positive.code: 
        interfaces = mkOption {
          default = [];
          description = ''
            List of network interfaces where listening for connections.
            When providing the empty list, `[]', lshd listens on all
  
negative.code: 
        hostKey = mkOption {
          default = "/etc/lsh/host-key";
          type = types.str;
          description = ''
            Path to the server's private key.  Note that this key must
            have been created, e.g., using "lsh-keygen --server |
  