title: scala merge option sequences
body: <p>Want to merge <code>val A = Option(Seq(1,2))</code> and <code>val B = Option(Seq(3,4))</code> to yield a new option sequence</p>
  
  <p><code>val C = Option(Seq(1,2,3,4))</code></p>
  
  <p>This</p>
  
  <p><code>val C = Option(A.getOrElse(Nil) ++ B.getOrElse(Nil))</code>, </p>
  
  <p>seems faster and more idiomatic than </p>
  
  <p><code>val C = Option(A.toList.flatten ++ B.toList.flatten)</code></p>
  
  <p>But is there a better way? And am I right that <code>getOrElse</code> is faster and lighter than <code>toList.flatten</code>?</p>