+- Signs in Generic Declaration in Scala

Question

I was looking at the documentation for PartialFunction in this link:

trait PartialFunction[-A, +B] extends (A) ⇒ B

Maybe someone can help clari

Answer 1

To supplement the other answers, here is a link to the documentation for variances on the scala-lang site:

https://docs.scala-lang.org/tour/variances.html