anchor.diff:    config = mkIf cfg.enable {
   
       assertions = [
  -      { assertion = cfg.groupAccess -> versionAtLeast cfg.package.version "11.0";
  +      { assertion = cfg.groupAccess == true -> versionAtLeast cfg.package.version "11.0";
           message = ''
             'groupAccess' is not available for PostgreSQL < 11.
           '';
  
positive.code:                   else "/var/db/postgresql");
  
      services.postgresql.initdbArgs =
        mkBefore (optional cfg.groupAccess "--allow-group-access");
  
      services.postgresql.authentication = mkAfter
        ''
  
negative.code:       ${cfg.extraConfig}
      '';
  
      dirMode = if cfg.groupAccess == true then "0750" else "0700";
  
  in
  
  