Undo a Vim script.

" Unsource a file
call unsource#unsource('/etc/vimrc.local')
" Unsource multiple files
call unsource#unsource(['/etc/vimrc.local', '/etc/vimrc'])
" Only undo 'set's and 'map's
call unsource#unsource('/etc/vimrc.local', 'sm')

The second argument to unsource#unsource can be used to configure which commands are undone. By default the commands are let, function, set, autocmd, and map. To undo only a subset pass a string containing the first letter of the commands (e.g., 'lsa').