How to run isort only for specific projects

gistfile1.txt

# ~/.vimrc
" Allow project specific vimrc files
set exrc
set secure " Prevent potentially malicious vimrc files from breaking stuff

" Isort
function! Isort()
    let cursor_pos = getpos('.')
    %!isort -
    call setpos('.', cursor_pos)
endfunction
command! -range=% Isort :<line1>,<line2>! :Isort()

...

# ~/projects/some_project/.vimrc
" This project has an ISort configuration
" So automatically sort imports according to its config
autocmd FileType python autocmd BufWritePre <buffer> :call Isort()



#################################
# Bonus for better buildout files
#################################
# ~/.vimrc
" Allow project specific vimrc files
set exrc
set secure " Prevent potentially malicious vimrc files from breaking stuff

" normalize buildout
function Normalizebuildout()
    let cursor_pos = getpos('.')
    %!normalize_buildout -
    call setpos('.', cursor_pos)
  endfunction
command! -range=% Normalizebuildout :Normalizebuildout()

$ cd $project
$ source bin/activate
$ pip install buildout_helpers

# ~/projects/some_project/.vimrc
" This project has an ISort configuration
" So automatically sort imports according to its config
autocmd BufWritePre *.cfg :call Normalizebuildout()