Scala implicits. It's a curried arg list you can omit, but the compiler checks that you have implicit values of all the needed types in scope. Or you can pass w

Scala implicits. It's a curried arg list you can omit, but the compiler checks that you have implicit values of all the needed types in scope. Or you can pass whatever you want explicitly. https://docs.scala-lang.org/tour/implicit-parameters.html https://docs.scala-lang.org/tour/implicit-parameters.html