title: PFUser logInWithUsernameInBackground in Swift - Missing argument for parameter 'target' call
body: <p>I am implementing the login function for Parse written in Swift. I am getting an error:</p>
  
  <blockquote>
    <p>Missing argument for parameter 'target' call</p>
  </blockquote>
  
  <p>It doesn't seem like I"m missing any parameters though - I'm following the declaration in PFUser.h.</p>
  
  <p>Here is my code:</p>
  
  <pre><code>//Declarations
  @IBOutlet weak var usernameTextField: UITextField!
  @IBOutlet weak var passwordTextField: UITextField!
  
  @IBAction func loginButtonPressed(sender: UIButton) {
      let userEmail = usernameTextField.text
      let userPassword = passwordTextField.text
  
      //Check that both fields are filled
      if usernameTextField != "" &amp;&amp; passwordTextField != "" {
          PFUser.logInWithUsernameInBackground(userEmail, password: userPassword) {
              (user: PFUser, error: NSError) -&gt; Void in {
      }
  }
  </code></pre>
  
  <p>Thank you for your help!</p>