实现一个scala集合,以便map,filter等生成正确的类型

import scala.collection.immutable.Seq

object ScalaCollectionExample {
  type MyCollection[+A] = Seq[A]

  def main(args: Array[String]): Unit = {
    val myCollection: MyCollection[Int] = MyCollection(1, 2, 3, 4, 5)

    val filteredCollection: MyCollection[Int] = myCollection.filter(_ % 2 == 0)
    val mappedCollection: MyCollection[Int] = filteredCollection.map(_ * 2)

    println(mappedCollection)
  }
}