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The CSG is contained in a single Python module almaqa2csg which is part of the the "analysis_scripts.tar" package. This package which also contains the "analysisUtils" which you will also need since the CSG uses a few of their functions.
See the Zenodo analysisUtils page (presently for version 2.49, 12 July 2023) (which provides a citeable DOI: 10.5281/zenodo.75021608140844) and the Analysis Utilities CASA Guide for details on how to install the package.
Be sure to check the Zeondo page for the presence of a later version. There are several releases per year.
Usage
With your sys.path set up to import the analysisUtils, type
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