Highlight argument names in function calls?

[HudsonMC16]

I could not find a way to highlight only the argument names in function calls. Is this possible using this plugin? To illustrate, to highlight the text wrapped in asterisks in the code snippet below:

function_with_many_args(
    *arg1*='testing',
    *arg2*='testing again',
    *arg3*='more testing'
)

[bew]

You can do it without the plugin in the meantime, here is what I do:
https://github.com/bew/dotfiles/blob/07d44f841d2f6ea9932754f44bd52e0623cde3ea/nvim/init.vim#L309-L311

" Add colors to 'arg=' in 'func_call(arg=1)'
autocmd FileType python syn match pythonFunctionCallKwargs '\h\w\+='
autocmd FileType python hi pythonFunctionCallKwargs ctermfg=137