title: Scala class with SortedMap and "reversed" SortedMap
body: <p>I'm a Scala novice. I'm looking to create a class in Scala with two mutable <code>SortedMap</code>s, one in normal sorted order (increasing) and one in reverse sorted order (decreasing)</p>
  
  <pre><code>class MyClass {
    var mapNormal : SortedMap[Int, Int] = SortedMap.empty
    var mapReversed : ??? = SortedMap.empty
  }
  
  var x  = new MyClass
  x.mapNormal += (1 -&gt; 50)
  x.mapReversed += (2 -&gt; 51)
  </code></pre>
  
  <p>How can I do this in Scala?</p>