SALT command for repositories for SLES 15 SP3

Hi there,

does anybody know to the SALT command looks like to add a custom channel in SUMA?

for sure, i can file.manage a repo file in /etc/zypp/repos.d/ but SUMA has its own file /etc/zypp/repos.d/susemanager:channels.repo where all repository urls are stored.

i want to install a fresh system, and then by adding a salt state channel repositories should be added
and additional packages should be installed.
( it should be done after bootstrapping)

can anybody send me a hint?
thanks a lot in advance!