i like thinking of solid an going back to first principles. There things i also think a get a bad rap because they're associated with heavy, heavy o o code bases that are just unmanageable. O turn about substitute ability. And so when we talk about duck typing and python, its o mortal types, arg can represent some behavior. It's expecting additionand subtraction. We mit addu addition an subtraction on dates and times. Another might do it on, like, imaginary numbers. But the concept of adding and subtracting things can reads it right? Some like yit. So things like liscop substitutn if teyl, excuse me, liscof