Is there a function to get the "parent" of a set?

[mcw0]

Create a quick select set.  Now create another quick select set that includes the first set.  "listSets" will give you the set an "object" is a member of.  But it won't for a set.  Is there a function that I'm unaware of that will return the "parent set" of any node, be they object or another set?

[tkaap2]

I'm getting results that seem like what you want from the listSets command.  Or else I'm not understanding the problem.  What Maya version are you seeing this failing in?
I created some poly primitives, and make a quick-select set "set1" containing them.  Then I created quick-select sets containing "set1" called "set2" and "set3".  Then listSets is returning both of the 'parent' sets, as expected.  This is what I'm getting on Windows in Maya 2019, 2020, and 2022.

listSets -object "set1";
// Result: set3 set2 //

[mcw0]

Thank you for looking into this.  I also have meshes along with "set1" under "set2" and "set3".  When I use "listSets -object", I only get the meshes.  I'm in Maya2019.  I'll try it again tomorrow.