title: Returning true if all items in a list are true, otherwise false
body: <p>I want to return true if "inStock" key exists AND all values in the list are true.
  If not, then return false.</p>
  
  <pre><code>val product = Map("ids" -&gt; List("1" ,"2", "3"), "inStock" -&gt; List("true", "false", "true", "true"))
  
  product.get("inStock").map(x =&gt; x.forall(true))  // doesnt' work currently
  
  &lt;console&gt;:13: error: type mismatch;
   found   : Boolean(true)
   required: String =&gt; Boolean
  </code></pre>
  
  <p>I should also safely parse the string value to a boolean like:</p>
  
  <pre><code>Try(x.toBoolean)
  </code></pre>