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trait Option[+a] {}
case class Some[a](x: a) extends Option[a] {
override def toString(): String = "Some(" + x + ")"
override def equals(that: Any): Boolean = that match {
case Some(x) => this.x == x
case _ => false
}
override def hashCode(): Int = getClass().hashCode() * 41 + x.hashCode()
}
case object None extends Option[Nothing] {
override def toString(): String = "None"
override def equals(that: Any) = that match {
case None => true
case _ => false
}
override def hashCode(): Int = getClass().hashCode()
}
object test {
def println(str: String): Unit = java.lang.System.out.println(str)
def print(opt: Option[String]) = opt match {
case Some(x) => println(x)
case None => println("nothing")
}
}
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