title: Assertion failure when trying to write data to Keychain
body: <p>I am trying to write some array data to my keychain using the code below</p>
  
  <pre><code>    // set up keychain so I can write to it... or read if needed (specially for testing)
      KeychainItemWrapper* keychain = [[KeychainItemWrapper alloc] initWithIdentifier:@"KeyKeychain" accessGroup:nil];
  
  //    write
      NSData *dataarr = [NSKeyedArchiver archivedDataWithRootObject:parsedRemoteSitesMutableArray];
       [keychain setObject:dataarr forKey:(__bridge id)(kSecAttrGeneric)];
  //    read
      NSData *myArr = [keychain objectForKey:(__bridge id)(kSecAttrGeneric)];
      NSArray *arrayCopy = [NSKeyedUnarchiver unarchiveObjectWithData:myArr];
  //    log
      NSLog(@"%@", arrayCopy);
  </code></pre>
  
  <p>as you can see I am converting my NSArray to NSData then trying to store the NSData into kSecAttrGeneric however I am reciving this error below when I tri to setObject:forKey</p>
  
  <pre><code>Assertion failure in -[KeychainItemWrapper writeToKeychain], /Users/imac/Documents/Iphone applications/appname/appname/KeychainItemWrapper.m:268
  2013-07-22 13:54:39.952 key[2167:907] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Couldn't add the Keychain Item.'
  *** First throw call stack:etc...
  </code></pre>
  
  <p>any help would be greatly appreciated.</p>