error:
       … while evaluating a branch condition
         at «string»:25:5:
           24|     v:
           25|     if !builtins.isAttrs v || isDrv v then
             |     ^
           26|       v

       … in the left operand of the OR (||) operator
         at «string»:25:28:
           24|     v:
           25|     if !builtins.isAttrs v || isDrv v then
             |                            ^
           26|       v

       … while evaluating definitions from `/nix/store/xfg4bws749i95jvnxhymxmfwailzk38q-source/modules/transposition.nix':

       … while evaluating definitions from `/nix/store/y1bbmk1b1dm8yyzymcybn9brxwva66sq-source/flake.nix, via option perSystem':

       … while evaluating the option `system.build.toplevel':

       … while evaluating definitions from `/nix/store/cc7ff4ysismx0c3778v8gc6b14plrz3z-source/nixos/modules/system/activation/top-level.nix':

       … while evaluating the option `warnings':

       … while evaluating definitions from `/nix/store/cc7ff4ysismx0c3778v8gc6b14plrz3z-source/nixos/modules/system/boot/systemd.nix':

       … while evaluating the option `systemd.services.litellm.serviceConfig':

       … while evaluating definitions from `/nix/store/cc7ff4ysismx0c3778v8gc6b14plrz3z-source/nixos/modules/services/misc/litellm.nix':

       … while evaluating definitions from `/nix/store/y1bbmk1b1dm8yyzymcybn9brxwva66sq-source/machines/pubproxy01/public-inference-proxy.nix':

       (stack trace truncated; use '--show-trace' to show the full, detailed trace)

       error: public-inference-proxy: expected exactly one upstream model group, got 2