How to define a method in Scala that returns a type? - Stack Overflow

How to define a method in Scala that returns a type? - Stack Overflow

You should just put =:

private def createDomNode(tag: String, attrs: Map[String , String]): DomNode = {      // ...  }

If you will not put = between method signature and body, then return type is Unit, so this:

def m(i: Int) {}

is the same as

def m(i: Int): Unit = {}

Read full article from How to define a method in Scala that returns a type? - Stack Overflow