text: import scalaz._
  import Scalaz._
  
  object SCL9752 {
    val l: List[Map[String, Int]] = List(Map("s" -> 4))
    val x = l.sequenceU
    x.<ref>map { case (a, b) => a } //can't resolve map
  
    val k: Map[String, List[Int]] = ??? //ok
    k.map { case (a, g) => a } //ok
  }
  