title: Is there a difference between [NSMutableDictionary dictionaryWithDictionary:] and mutableCopy?
body: <p>Is there a difference between the following ways to create a mutable dictionary?</p>
  
  <pre><code>NSMutableDictionary *dict = [NSMutableDictionary dictionaryWithDictionary:dict2];
  
  NSMutableDictionary *dict = [dict2 mutableCopy]
  </code></pre>