I actually encountered this in Scala (my example originally had [square brackets] rather than <pointy ones>). My `.has` method uses cats.Eq and is monkey-patch

I actually encountered this in Scala (my example originally had [square brackets] rather than <pointy ones>). My `.has` method uses cats.Eq and is monkey-patched on to the Iterable interface: implicit final class IOps[A: cats.Eq](val i: Iterable[A]) { def has(x: A): Boolean = i.exists(_.eqv(x)) }