How can a group be made optional?
Like (.....)?
Currently, as a workaround, I can copy the resulted rex string and insert manually the question mark and insert it to the re_matches.

I would like to parse a file having similar structure, lines containing 1 or more (but limited) id key-value pairs.

a=aa, id=4, b=bb, c=cc, d=dd
a=aa, id=4, b=bb, id=45, c=cc
a=aa, id=4, b=bb, id=22, cc=c ,id=444, cc=aaa