This is a static property, which means it's effectively a handy way to get a predefined animation. You'd use `Animation.easeIn` to get an animation which, as Claude points out, will start slowly and increase in speed.
It sounds like you're under the impression that these are properties of an Animation instance though. If that's the case, I'm afraid that's not what they are. They're effectively factory methods (if you're familiar with that term) returning a new Animation instance that's configured in a certain way. We don't actually have access to any of the real properties of the Animation type. If you are interested in how to define your own animations, however, you can look at WWDC19 session 237 which discusses animations and transitions at around the 34 minute mark.