title: How to exclude a list of PFUsers in a PFUser.query()?
body: <p>How to exclude a list of PFUsers in a PFUser query (in Swift)? I used to use </p>
  
  <pre><code> query.whereKey("username", notEqualTo: PFUser.currentUser()!.username!)
  </code></pre>
  
  <p>to exclude the currentUser. The addition of username doesn't feel right and it gets messy if it is a list of PFUsers and I want to exclude (To create a list of usernames? feels not a good answer)</p>
  
  <p>More importantly, what if this list of PFUsers is the key value as result of another PFQuery? How to achieve something like</p>
  
  <pre><code>PFUser.query.where ... doesNotMatchKey: "followedUser", inQuery: relationQuery)
  </code></pre>