Checking Contracts with satisfies
impl.test.close = "CHANEL_CLOSE_MASSAGE";
// ^
// Type '"CHANEL_CLOSE_MASSAGE"' is not assignable
// to type '"CHANNEL_CLOSE"'.(2322)
impl.test.close = "CHANEL_CLOSE_MASSAGE";
// ^
// Type '"CHANEL_CLOSE_MASSAGE"' is not assignable
// to type '"CHANNEL_CLOSE"'.(2322)