title: objective-c Accessing array given as value of NSDictionary
body: <p>let's say i have a nsdictionary which contains an array as value. </p>
  
  <pre><code>NSMutableDictionary *test = [NSMutableDictionary dictionaryWithObjectsAndKeys:
  [[NSMutableArray alloc]initWithObjects:"@Audi",@"Mercedes",@"Ferrari",nil], @"box 1",
  [[NSMutableArray alloc]initWithObjects:"@Chervrolet",@"Mercedes",@"Bentley",nil], @"box 2",
  [[NSMutableArray alloc]initWithObjects:"@Audi",@"Dodge",@"Ferrari",nil], @"box 2",
  nil]
  </code></pre>
  
  <p>that's my simple dictionary with the arrays inside.
  well now i need to check if theres a value in it.</p>
  
  <p>here how i check if theres a certain key</p>
  
  <pre><code>if([test objectForKey@"box 2"]) { NSLog(@"item exists"); }
  </code></pre>
  
  <p>how can i access now the array inside one of the value? let's say to check if the array contains an item or to add one?</p>
  
  <p>let's say i want to check if box 2 contains an Audi, and if not, i want to add it</p>