Hammer spoon display sleep when Dolphin is open

init.lua

function applicationWatcher(appName, eventType, appObject)
    if (appName == "Dolphin") then
        if (eventType == hs.application.watcher.launched) then
            hs.caffeinate.set('displayIdle', true)
        elseif (eventType == hs.application.watcher.terminated) then
            hs.caffeinate.set('displayIdle', false)
        end
    end
end

local appWatcher = hs.application.watcher.new(applicationWatcher)
appWatcher:start()