contract flipper { bool private value = true; @payer(payer) constructor() { print("Hello, World!"); } /// A message that can be called on instantiated contracts. /// This one flips the value of the stored `bool` from `true` /// to `false` and vice versa. function flip() public { value = !value; } /// Simply returns the current value of our `bool`. function get() public view returns (bool) { return value; } }