title: How to create model classes using JSONModel?
body: <p>I am trying to create Model Class by using <a href="https://github.com/icanzilb/JSONModel" rel="nofollow">JSONModel</a>.My json Dictionary after using <code>NSJSONSerialization</code> looks like below.</p>
  
  <pre><code>      {
  apiStatus =     {
      message = SUCCESS;
      success = 1;
  };
  boardingPoints = "&lt;null&gt;";
  inventoryType = 0;
  seats =     (
              {
          ac = 0;
          available = 1;
          bookedBy = "&lt;null&gt;";
          commission = "&lt;null&gt;";
          fare = 1200;
  
  
      },
              {
          ac = 0;
          available = 1;
          bookedBy = "&lt;null&gt;";
          commission = "&lt;null&gt;";
          fare = 1200;
  
  
      },
  
    );
  }
  </code></pre>
  
  <p>The JSON looks like this:</p>
  
  <pre><code>   {"boardingPoints":null,"inventoryType":0,"apiStatus":{"success":true,"message":"‌​SUCCESS"},"seats":[{"fare":1200,"commission":null,"bookedBy":null,"ac":false,"ava‌​ilable":true},{"fare":1200,"commission":null,"bookedBy":null,"ac":false,"availabl‌​e":true},]}
  </code></pre>
  
  <p>I have a model class like this :-</p>
  
  <pre><code> @interface Seat : JSONModel
  
   @property (nonatomic,strong)NSString *ac;
   @property (nonatomic,strong)NSString *available;
   @property(nonatomic,strong)NSString *bookedBy;
   @property(nonatomic,strong)NSString *comission;
   @property(nonatomic)NSNumber * fare;
  </code></pre>
  
  <p>For mapping keys I have done like this:-</p>
  
  <pre><code> +(JSONKeyMapper*)keyMapper {
  return [[JSONKeyMapper alloc] initWithDictionary:@{@"ac":@"ac",
                                                     @"available":@"available",
                                                     @"bookedBy":@"bookedBy",
                                                     @"commission":@"commission",
                                                     @"fare":@"fare", }];
  </code></pre>
  
  <p>} </p>
  
  <p>However when I try to use this model I get the following error:</p>
  
  <pre><code>[JSONModel.m:252] Incoming data was invalid [Seat initWithDictionary:]. Keys missing: {(
  bookedBy,
  comission,
  available,
  ac,
  fare,
  
  )}
  
  Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[__NSPlaceholderArray initWithObjects:count:]: attempt to insert nil object from objects[0]'
  </code></pre>
  
  <p>I am using it like this:</p>
  
  <pre><code> //Using JSON Model.
      NSError *jsonError;
      seat = [[Seat alloc]initWithDictionary:jsonDictionary error:&amp;jsonError];
      jsonArray = @[seat.ac,seat.available,seat.bookedBy,seat.comission,seat.fare];
      NSLog(@"JSON Model Array : %@", jsonArray);
  </code></pre>
  
  <p>How to use it correctly? </p>