$ nix-build -A headphones
these 2 derivations will be built:
  /nix/store/y8w8yvjxfsjrjz38hc7m7c5kapj7ha4z-source.drv
  /nix/store/x0bslibsa9540d4rjv42zvs6s2nga5fg-headphones-0.6.0-alpha.1.drv
building '/nix/store/y8w8yvjxfsjrjz38hc7m7c5kapj7ha4z-source.drv'...

trying https://github.com/rembo10/headphones/archive/v0.6.0-alpha.1.tar.gz
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   134  100   134    0     0    558      0 --:--:-- --:--:-- --:--:--   560
100 3684k    0 3684k    0     0  3726k      0 --:--:-- --:--:-- --:--:-- 6293k
unpacking source archive /private/tmp/nix-build-source.drv-0/v0.6.0-alpha.1.tar.gz
building '/nix/store/x0bslibsa9540d4rjv42zvs6s2nga5fg-headphones-0.6.0-alpha.1.drv'...
Sourcing python-remove-tests-dir-hook
Sourcing python-catch-conflicts-hook.sh
Sourcing python-remove-bin-bytecode-hook.sh
Sourcing setuptools-build-hook
Using setuptoolsBuildPhase
Using setuptoolsShellHook
Sourcing pip-install-hook
Sourcing python-imports-check-hook.sh
Using pythonImportsCheckPhase
Sourcing python-namespaces-hook
unpacking sources
unpacking source archive /nix/store/82v6spcdizlkx9gz94k1cgwvgrgynrin-source
source root is source
setting SOURCE_DATE_EPOCH to timestamp 315619200 of file source/setup.cfg
patching sources
configuring
no configure script, doing nothing
installing
post-installation fixup
strip is /nix/store/j5bv1crdxnsvdj1w70445lfg63amq0gy-cctools-binutils-darwin-949.0.1/bin/strip
stripping (with command strip and flags -S) in /nix/store/dic3nr75fiy9rzb1yfwbk73s8jvr86vw-headphones-0.6.0-alpha.1/bin 
patching script interpreter paths in /nix/store/dic3nr75fiy9rzb1yfwbk73s8jvr86vw-headphones-0.6.0-alpha.1
/nix/store/dic3nr75fiy9rzb1yfwbk73s8jvr86vw-headphones-0.6.0-alpha.1/opt/headphones/lib/twitter/api.py: interpreter directive changed from "#!/usr/bin/env python" to "/nix/store/fkygdjhm2raz32xrzwnq8b89hkkdc9vv-python3-3.9.9/bin/python"
/nix/store/dic3nr75fiy9rzb1yfwbk73s8jvr86vw-headphones-0.6.0-alpha.1/opt/headphones/lib/pynma/pynma.py: interpreter directive changed from "#!/usr/bin/python" to "/nix/store/fkygdjhm2raz32xrzwnq8b89hkkdc9vv-python3-3.9.9/bin/python"
/nix/store/dic3nr75fiy9rzb1yfwbk73s8jvr86vw-headphones-0.6.0-alpha.1/opt/headphones/Headphones.py: interpreter directive changed from "#!/usr/bin/env python" to "/nix/store/fkygdjhm2raz32xrzwnq8b89hkkdc9vv-python3-3.9.9/bin/python"
Rewriting #! /nix/store/b0q4wjdw6xwhfsqy8ab106cmhn5xrr8p-bash-5.1-p12/bin/bash -e to #!/nix/store/fkygdjhm2raz32xrzwnq8b89hkkdc9vv-python3-3.9.9
Executing pythonRemoveTestsDir
Finished executing pythonRemoveTestsDir
pythonCatchConflictsPhase
pythonRemoveBinBytecodePhase
pythonImportsCheckPhase
Executing pythonImportsCheckPhase
/nix/store/dic3nr75fiy9rzb1yfwbk73s8jvr86vw-headphones-0.6.0-alpha.1