anchor.diff:  
         configFile = mkOption {
           default = confFile;
  -	example = ''pkgs.writeText "httpd.conf" "# my custom config file ...";'';
  +        example = literalExample ''pkgs.writeText "httpd.conf" "# my custom config file ...";'';
           description = "
             Overridable config file to use for Apache. By default, use the
             file automatically generated by nixos.
  
positive.code:               ${perServerConf false vhost}
            </VirtualHost>
          '';
        in concatMapStrings makeVirtualHost vhosts
      }
    '';
  
  
negative.code: 
    mainSubservices = subservicesFor mainCfg;
  
    allSubservices = mainSubservices ++ concatMap subservicesFor mainCfg.virtualHosts;
  
  
    # !!! should be in lib
  