error:
       … while calling the 'genericClosure' builtin
         at /pwd/lang/eval-fail-genericClosure-startSet-not-list.nix:1:1:
            1| builtins.genericClosure {
             | ^
            2|   startSet = "not a list";

       … while evaluating the 'startSet' attribute passed as argument to builtins.genericClosure

       error: expected a list but found a string: "not a list"