How do we open "Keyboard Viewer"?

How do we open Keyboard Viewer programatically? I am working on Sonoma Mac Application.

I could open "Emoji & Symbols" programatically as follows.

NSArray *sources = (__bridge NSArray*)TISCreateInputSourceList(nil, false);

TISInputSourceRef keyboardViewer = (__bridge TISInputSourceRef)[sources objectAtIndex: 2]; // "Emoji & Symbols" is the 3rd one. So 2. 

TISSelectInputSource(keyboardViewer);

CFRelease((CFTypeRef)sources);	

After some searching, Keyboard Viewer could be opened with similiar approach with above in the old previous version of MacOS.

I have a strong feeling there is a way to bring up the keyboard because we can bring up "Emoji & Symbols". I mean, why would apple prevent us to show Keyboard Viewer.

Any idea?