This is makeindex, version 2.15 [TeX Live 2019] (kpathsea + Thai support).
Scanning style file ./python.ist.......done (7 attributes redefined, 0 ignored).
Scanning input file MOM6.idx....done (108 entries accepted, 0 rejected).
Sorting entries....done (748 comparisons).
Generating output file MOM6.ind....done (252 lines written, 0 warnings).
Output written in MOM6.ind.
Transcript written in MOM6.ilg.