# This function provides specific bits for building a flit-based Python package. { python , flit }: { ... } @ attrs: attrs // { buildInputs = [ flit ]; buildPhase = attrs.buildPhase or '' runHook preBuild flit build --format wheel runHook postBuild ''; # Flit packages, like setuptools packages, might have tests. installCheckPhase = attrs.checkPhase or '' ${python.interpreter} -m unittest discover ''; doCheck = attrs.doCheck or true; }