Hello, I'm using macOS Sierra and I want to change some alerts' sounds to match my iPad. For example incoming mail to sound "Aurora" and calendar events to "Alert" (these sounds are built-in iOS). But on Mac, I can choose only from few selected sounds and I can't add my own sounds. Unfortunately, "Aurora" and "Alert" are not in list. I have these sound files as standalone files, but I can't add them to list. Any idea?