title: Assigning to 'id<UITextFieldDelegate> _Nullable' from incompatible type 'HomeDataForm *const __strong'
body: <p>I get the above warning message listed with the following code:</p>
  
  <pre><code>self.classNumberTF.delegate = self;
  </code></pre>
  
  <p>classNumberTF is a textField and a subview of a UIView of self. Self is of type NSObject (HomeDataForm). I use this line of code so that when the user taps "Done" on the keyboard, the keyboard is then dismissed. So it does what I intend, but I am not sure why I am getting the warning. I don't recall receiving this warning until after installing xcode 7. Thank you.</p>