main.go

// package decls, imports...

// Hooman & Pet interfaces...
// Person & Dog structs...

func PlayAround(type H Hooman, P Pet)(human H, pet P) {
  fmt.Println("The human says:", human.Speak())
  fmt.Println("And the pet responds:", pet.ProduceSound())
}

func main() {
  PlayAround(Person{}, Dog{})
}