this derivation will be built:
  /nix/store/cx8y391f68ch4xrk8vy402qx7xzz5nrs-check-letta-code.drv
building '/nix/store/cx8y391f68ch4xrk8vy402qx7xzz5nrs-check-letta-code.drv'

upload niks3: ok