anchor.diff:            Port ${toString port}
           '') cfg.ports}
   
  +        ${concatMapStrings ({ port, addr }: ''
  +          ListenAddress ${addr}${if port != null then ":" + toString port else ""}
  +        '') cfg.listenAddresses}
  +
           ${optionalString cfgc.setXAuthLocation ''
               XAuthLocation ${pkgs.xorg.xauth}/bin/xauth
           ''}
  
positive.code:         description = ''
            Specifies on which ports the SSH daemon listens.
          '';
        };
  
        passwordAuthentication = mkOption {
  
negative.code:         assertion = (data.publicKey == null && data.publicKeyFile != null) ||
                      (data.publicKey != null && data.publicKeyFile == null);
          message = "knownHost ${name} must contain either a publicKey or publicKeyFile";
        })
        ++ flip map cfg.listenAddresses ({ addr, port }: {
          assertion = addr != null;
          message = "addr must be spefied in each listenAddresses entry";
        });
  
    };
  