title: 'NSInvalidArgumentException', reason: 'Invalid type in JSON write (_SwiftValue)' with alamofire swift3
body: <p>I've encountered following error while uploading Swift3 using XCode8.</p>
  
  <blockquote>
    <p>'NSInvalidArgumentException', reason: 'Invalid type in JSON write
    (_SwiftValue)'</p>
  </blockquote>
  
  <pre><code>let param: Parameters = [
      "email":txrNRC.text as AnyObject,
      "password":txtPassword.text as AnyObject
  ]
  </code></pre>
  
  <p>Please let me know how to solve that issue. I've already tried with <code>let param: NSDictionary</code> but got same error message.</p>