Vim Snippets expand trigger functon

snippets_expand_trigger.vim

function! Neoj()
    if pumvisible() == 1
        return "\<C-n>"
    else
        call UltiSnips#JumpForwards()
        if g:ulti_jump_forwards_res == 0
            return "\<C-j>"
        endif
        return ""
    endif
endfunction

function! Neok()
    if pumvisible() == 1
        return "\<C-p>"
    else
        call UltiSnips#JumpBackwards()
        if g:ulti_jump_backwards_res == 0
            return "\<C-k>"
        endif
        return ""
    endif
endfunction

let g:UltiSnipsJumpForwardTrigger = "<nop>"
let g:UltiSnipsJumpBackwardTrigger = "<nop>"
inoremap <silent> <C-j> <C-R>=Neoj()<CR>
snoremap <silent> <C-j> <Esc>:call UltiSnips#JumpForwards()<CR>
inoremap <silent> <C-k> <C-R>=Neok()<CR>
snoremap <silent> <C-k> <Esc>:call UltiSnips#JumpBackwards()<CR>