I am trying to debug my init file: C-u prefix is not working. I am using the elisp-bug-hunter package that has saved me many times in the past. But it doesn't work fine this time though, so it seems I need an “assertion elisp” to debug my init file. What elisp expression would return nil when C-u prefix works and non-nil when C-u prefix doesn't work? I have tried (eq (key-binding "C-u C-SPC") 'nil) but it is probably a nonsense. Best regards