Saving colorscheme to session file on exit

[j-krl]

Is there a way you could recommend that I save my current colorscheme to the session file before exiting vim? With regular old :mksession I can do it pretty easily with an autocmd that triggers on SessionWritePost where I write an extra line to the session file. This doesn't seem to work with vim-obsession.

I noticed there's an g:obsession_append variable in the plugin source, but I don't think it will work for something dynamic like the current colorscheme.