why autopep2 doesnt work in vim?

[nickhuangxinyu]

I want to install autopep8 plugin in my vim (os : centos8)

here is my install command:

pip install autopep8 write .vimrc config like this:

let g:autopep8_disable_show_diff=1
autocmd FileType python2 noremap <buffer> <F8> :call Autopep8()<CR>

set nocompatible              " required
filetype off                  " required
set backspace=2
set rtp+=/.vim/bundle/Vundle.vim
call vundle#begin('/.vim/bundle/')
Plugin 'Valloric/YouCompleteMe'
Plugin 'gmarik/Vundle.vim'
Plugin 'scrooloose/nerdtree'
"Plugin 'zxqfl/tabnine-vim'
"Plugin 'Lokaltog/vim-powerline'
Plugin 'tell-k/vim-autopep8'
"Plugin 'nvie/vim-flake8'
call vundle#end()            " required
filetype plugin indent on    " required
let g:ycm_global_ycm_extra_conf='/.ycm_extra_conf.py'
let g:ycm_server_python_interpreter = '/usr/bin/python2'
let g:ycm_max_diagnostics_to_display = 0 
set encoding=utf-8

then:

PlginInstall install is good, but after that, i cant use Autopep8 in my vim, can you help on this?