title: Equivalent of a predicate's ANY for Swift 3 filter expression
body: <p>When using a predicate, we can have:</p>
  
  <pre><code>filterPredicate = [NSPredicate predicateWithFormat:@"(ANY names.firstName contains[c] %@), nameToSearchFor];
  </code></pre>
  
  <p>This use of <code>ANY</code> allows us to find any object where any of the objects in the names collection has a <code>firstName</code> containing the desired text.</p>
  
  <p>Is it possible to do something similar with filter expressions in Swift 3? In other words, something like:</p>
  
  <pre><code>allPeople.filter { $0.(ANY)names.firstName.contains(searchString) };
  </code></pre>
  
  <p>(The above ANY syntax is made up for illustration).</p>
  
  <p>Perhaps could be done by nesting a <code>reduce</code> that concatenates all the firstNames, then see if my target string is contained in that?</p>