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trait Functor[F[_]]
def map[A,B](fa: F[A])(f: A => B): F[B]
sealed trait Option[+A]
case object None extends Option[Nothing]
case class Some[+A](value: A) extends Option[A]
given Functor[Option]
def map[A,B](fa: Option[A])(f: A => B): Option[B] = fa match
case None => None
case Some(x) => Some(f(x))
object Main extends App
println("Hello")
println(Some(2).map(_*2)) // ? некомпилитсяVH
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