title: max value of string in realm
body: <p>I intended to get the max value of <code>string</code> type in <code>Realm</code> by <code>maxOfProperty</code> method as follows:</p>
  
  <pre><code>[[MyRealmObject allObjects] maxOfProperty:propertyName]
  </code></pre>
  
  <p>However, I encountered the following error:</p>
  
  <blockquote>
    <p>maxProperty is not supported for string property</p>
  </blockquote>
  
  <p>Considering I can't change the type of property, what should I do now?</p>