:source session.vim is making vim-which-key not work properly about vim-which-key HOT 2 CLOSED

    function UnmapPluginsBindings()
    if ! empty(maparg('<leader>b', 'n')) 
    unmap <leader>b
    endif
    if ! empty(maparg('<leader>d', 'n')) 
    unmap <leader>d
    endif
    endf
    set timeoutlen=300
    nnoremap <silent> <leader> :call UnmapPluginsBindings() <bar> :WhichKey '<Space>'<CR>
    let g:which_key_map =  {}
    let g:which_key_map.f = { 'name' : '+file' }
    let g:which_key_map.f.f = { 'name' : 'file paths' }
    let g:which_key_map.h = { 'name' : '+hunk' }
    let g:which_key_map.g = { 'name' : '+git' }
    let g:which_key_map.w = { 'name' : 'window' }
    let g:which_key_map.s = { 'name' : 'session' }
    let g:which_key_map.y = { 'name' : 'ycm' }
    let g:which_key_map.d= {
      \ 'name' : '+Django' ,
      \ 'c' : ['DjangoTestClass'        , 'test class']        ,
      \ 'a' : ['DjangoTestApp'        , 'test app']        ,
      \ }
    let g:which_key_map.b= {
    \ 'name' : '+buffer' ,
    \ 'b' : ['<Plug>(CommandTBuffer)'        , 'Command-t' ]        ,
    \ '1' : ['b1'        , 'buffer 1']        ,
    \ '2' : ['b2'        , 'buffer 2']        ,
    \ 'd' : ['bd'        , 'delete-buffer']   ,
    \ 'D' : ['bd!'       , 'delete-buffer']   ,
    \ 'f' : ['bfirst'    , 'first-buffer']    ,
    \ 'h' : ['Startify'  , 'home-buffer']     ,
    \ 'l' : ['blast'     , 'last-buffer']     ,
    \ 'n' : ['bnext'     , 'next-buffer']     ,
    \ 'p' : ['bprevious' , 'previous-buffer'] ,
    \ '?' : ['Buffers'   , 'fzf-buffer']      ,
    \ }
    autocmd! User vim-which-key call UnmapPluginsBindings() | which#register('<Space>', 'g:which_key_map')
    call which_key#register('<Space>', "g:which_key_map")
    " nnoremap <silent> <leader> :<c-u>WhichKey '<Space>'<CR>
    " vnoremap <silent> <leader> :<c-u>WhichKeyVisual '<Space>'<CR>