classDiagram
	Animal <|-- Duck
	Animal <|-- Fish
	Animal <|-- Zebra
	Animal : +int age
	Animal : +String gender
	Animal: +isMammal()
	Animal: +mate()
	class Duck{
		+String beakColor
		+swim()
		+quack()
	}
	class Fish {
		-int sizeInFeet
		-canEat()
	}
	class Zebra{
		+bool is_wild
		+run()
	}

	callback Duck callback "Tooltip"
	link Zebra "https://www.github.com" "This is a link"
