title: How to export multiple maps to csv in Scala?
body: <p>How can I export all these maps to a single csv file using scala? mapKey contains all keys from all the maps, but not all of the (language) maps may have a value for a certain key. 
  The head row should contain "key", "default", "de", "fr", "it", "en"</p>
  
  <pre><code>val mapDefault: Map[String, String] = messages.getOrElse("default",Map())
  
  val mapDe: Map[String, String] = messages.getOrElse("de", Map())
  
  val mapFr: Map[String, String] = messages.getOrElse("fr", Map())
  
  val mapEn: Map[String, String] = messages.getOrElse("en", Map())
  
  val mapIt: Map[String, String] = messages.getOrElse("it", Map())
  
  var mapKey: Set[String] = mapDefault.keySet ++ mapDe.keySet ++ 
  mapFr.keySet ++ mapEn.keySet ++ mapIt.keySet
  </code></pre>