title: Cannot subscript a value of type '[String : String]?' with an index of type 'String'
body: <pre><code>   let orch = NSUserDefaults().dictionaryForKey("orch_array")?[orchId] as? [String:String]
     orch[appleId]
  </code></pre>
  
  <p>Errors on the <code>orch[appleId]</code> line with:</p>
  
  <blockquote>
    <p>Cannot subscript a value of type '[String : String]?' with an index
    of type 'String'</p>
  </blockquote>
  
  <p>WHY?</p>
  
  <p>Question #2:</p>
  
  <pre><code>   let orch = NSUserDefaults().dictionaryForKey("orch_array")?[orchId] as! [String:[String:String]]
     orch[appleId] = ["type":"fuji"] 
  </code></pre>
  
  <p>Errors with: "Cannot assign the result of this expression"</p>