title: Using fold to sum List of object attributes
body: <p>In this code I'm attempting to double each value and then sum v : </p>
  
  <pre><code>case class s(v : Int)
    val l = List(s(2) , s(3))                      
    l.fold(0) ((_.v * 2) + (_.v * 2))
  </code></pre>
  
  <p>But I receive error : </p>
  
  <pre><code>  value v is not a member of Any
  </code></pre>
  
  <p>How can I perform an operation on each attribute of the object within the List?</p>