title: How to deconstruct map to list?
body: <p>I have a List that contain country, I used groupBy to group them by country and now i would like to get fallowing result (for recycled view):</p>
  <pre><code>Country1
  Airport1
  Airport2
  Airport3
  Country2
  Airport4
  Airport5
  Airport6
  </code></pre>
  <p>could someone give me a tip on how to do this?
  My data class:</p>
  <pre><code>data class Airport(
  val city: City,
  val code: String,
  val country: Country,
  val name: String,
  </code></pre>
  <p>)</p>