Help with install on command

[Th3Whit3Wolf]

I am trying to install vim-which-key but am having issues

pack install liuchengxu/vim-which-key --on WhichKey,WhichKey!

Changed vimrc

autocmd! User WhichKey packadd vim-which-key | call which_key#register('<Space>', 'g:which_key_map')

let g:mapleader = "\<Space>"
nnoremap <silent> <leader> :<c-u>WhichKey '<Space>'<CR>
vnoremap <silent> <leader> :<c-u>WhichKeyVisual '<Space>'<CR>
" Define prefix dictionary
let g:which_key_map =  {}

let g:which_key_map.f = { 'name' : '+file' }

nnoremap <silent> <leader>fs :update<CR>
let g:which_key_map.f.s = 'save-file'

let g:which_key_map =  {}
let g:which_key_map.f = { 'name' : '+file' }
nnoremap <silent> <leader>fs :update<CR>
let g:which_key_map.f.s = 'save-file'
nnoremap <silent> <leader>fd :e $MYVIMRC<CR>
let g:which_key_map.f.d = 'open-vimrc'
nnoremap <silent> <leader>oq  :copen<CR>
nnoremap <silent> <leader>ol  :lopen<CR>
let g:which_key_map.o = {
      \ 'name' : '+open',
      \ 'q' : 'open-quickfix'    ,
      \ 'l' : 'open-locationlist',
      \ }
nnoremap <silent> <leader>fd :e $MYVIMRC<CR>
let g:which_key_map.f.d = 'open-vimrc'
nnoremap <silent> <leader>oq  :copen<CR>
nnoremap <silent> <leader>ol  :lopen<CR>
let g:which_key_map.o = {
      \ 'name' : '+open',
      \ 'q' : 'open-quickfix'    ,
      \ 'l' : 'open-locationlist',
      \ }

As is suggested by the author but it doesn't work.

I get back

Not an editor command: WhichKey ' '

When running

packadd vim-which-key | call which_key#register('<Space>', 'g:which_key_map')

Everything works as expected

[Th3Whit3Wolf]

I just made my own command and set vim-which-key as optional.