Is there a sample for converting other catalogues to catsHTM format?

[fockez]

The catsHTM is excellent for catalogue searching for photometry calibration.
But when I doing bright star crossmatching, I found that no catalogue can provide bright star sdss magnitude. The bright end is about 9 magnitude for APASS which is the main source of several other catalogue.
After searching, there is a ATLAS-REFCAT2 catalogue compiled by Tonry published at 2018. They have small telescopes called pathfinder, which can cover the bright end of the sky. Also it includes PanSTARRS DR1, ATLAS re-flattened APASS, SkyMapper DR1, APASS DR9, Tycho-2, and the Yale Bright Star Catalog. It is a great help for photometry calibration in some cases. So I want to convert the catalogue to catsHTM format.
Is there python tool for doing this? Or some sample that can be referencing.
Thanks.