Vim Sort Php Use

.vimrc

// Sort PHP use imports by length
// You don't have to select the use imports, hitting <leader>su anywhere in your file
// will sort the imports and put your cursor back where you left off.
//
// Replace ^M by hitting <C-v><C-m> in insert mode

function! SortPhpUseByLength()
    exec 'normal mrgg/^use\s^Mma/^class\s^M/^use\s^MNmb:nohlsearch^M:''a,''b! awk ''{ print length(), $0 | "sort -n | cut -d\\  -f2-" }''^M''r'
endfunction
nmap <leader>su :call SortPhpUseByLength()<cr>