Yes, it’s the same env var, it’s just a convenience method, for taking the current PYTHONPATH value and adding a new string to the end of it separated by the path separator. It runs this code essentially:
You could do it your self, but just make sure you don’t overwrite the current PYTHONPATH value as Toolkit won’t bootstrap, you must append to it.
I’m guessing you created the settings.tk-multi-launchapp.maya: block? You shouldn’t normally need to do this. I posted on the other thread you replied to with the instructions on how to add the hook:
Though technically the error you are getting is that your tk-maya.yml doesn’t know where to find the settings.tk-multi-launchapp.maya: settings block, as you probably haven’t included the tk-multi-launchapp.yml in the includes section of the file. However I think this is the wrong approach anyway, so I would follow the steps in the other post and see if that works for you. (And remove changes you made to the tk-maya.yml and tk-multi-launchapp.yml.)
Hope that helps, let me know if anything is not clear and I’ll try to clarify!
Cheers
Phil