Unable to install Python package "pusectl-asyncio", getting "No module named setuptools"

I’m trying to install pulsectl-asyncio onto my NixOS system:

I’ve Googled to the best of my abilities and arrived at this in my systemPackages:

(python311.withPackages (ps:
  with ps;
    # ...

    (buildPythonPackage rec {
      pname = "pulsectl-asyncio";
      version = "1.1.1";
      format = "pyproject";
      src = fetchPypi {
        inherit pname version;
        sha256 = "sha256-tZdrDd0jXZzMNFWgO+Zk98siAclCmTsDzraznZzqitA=";

      # Dependencies
      propagateBuildInputs = [

This seems like it should work, but it doesn’t build:

ModuleNotFoundError: No module named ‘setuptools’

Even though I have setuptools specified in propagateBuildInputs. What have I done wrong here?