Hi Thank you, Andreas, for your review. When #:tests? #t​ the following output is generated (and the build fails) > running test > WARNING: Testing via this command is deprecated and will be removed in a future version. Users looking for a generic test entry point independent of test runner are encouraged to use tox. I am not sure how to achieve this using our package management system and am not sure if it would be of great gain to do so. According to the documentation [1] ipython, matplotlib, etc are optional dependencies. I wouldn't include them per se since one can easily invoke a Guix shell providing these. To test one can invoke a guix shell --pure python-scapy python-ipython​ and run scapy​ manually. I have adjusted the patch, thank you for your time and effort in advance! Please let me know if i can improve it some more! g 1: https://scapy.readthedocs.io/en/latest/installation.html#optional-dependencies 2: https://scapy.net/