Hi im probably missing something here but how do i import a class when using the language server?

In the docs on the develop branch it states that the import class code action is available (https://phpactor.readthedocs.io/en/develop/lsp/support.html) but i cant for the life of me work out what i need to do to run it.

my assumption would be something along the lines of nmap <Leader>u <Plug>(coc-import-class)

Thanks.