How to Fit a TH3?

I’m having problems finding the right methods to fit a TH3. Specially, I’m trying to fit a TH3 to a guassian. I tried to use the Fit(“guas”) method but that seems to work only for TH1. The only thing I could find in the documentation for TH3 about fitting was FitSlicesZ() which is not what I’m looking for.

Can someone point to me to the documentation for this method? (Or tell me what it is if the documentation does not exist.)