On 05-09-2022 13:26, guix-patches--- via wrote:
> I have encountered the same problem as in this email:
> https://lists.gnu.org/archive/html/help-guix/2019-06/msg00073.html
>
> I do not understand how to apply the proposed fix.
>
IIRC, python-build-system uses G-exps nowadays, so to use #$, all you 
need to do is replace

(arguments `(#:phases (modify-phases ...)))

by

(arguments (list #:phases #~(modify-phases ...))),

no need for separate inputs.