先这样

Side effect: anything that causes an internal change of state is generating side effect.
讲讲这个：
def funcname(input: Any): Unit = {}

try {
//code
} catch (ExceptionType name) {

} finally {
//close everything
}

Scala has three ways to handle errors: Try[T], Option[T], and Either[L, R]
val greeting: Option[String] = Some(“Hello world”)
case class Coffee(name: String, price: Double)