title: Terminating app due to uncaught exception "NSInvalideArgumentException"
body: <p>I have my custom class Users which have several fields. e.g. username, password, first name, last name.</p>
  
  <p>i have an object of Users class user. when i want to set the text of UILabel of UITableviewCell it giving me the following exception:</p>
  
  <p>Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFDictionary firstName]: unrecognized selector sent to instance 0x755f510'</p>
  
  <p>my code is:</p>
  
  <pre><code>self.user = [usersArray objectAtIndex:indexPath.row];
  
  ((UILabel *)[cell viewWithTag:19]).text = user.firstName;
  ((UILabel *)[cell viewWithTag:20]).text = user.lastName;
  ((UILabel *)[cell viewWithTag:21]).text = user.username;
  </code></pre>