Using localized indexed collation in my tableview
===

I am following [apple's sample code - SimpleIndexedTableView][1] to get indexed my tableView. 
In there, I am struggling with `UILocalizedIndexedCollation`. 
Similar to the apple's sample code with the lines,

    
    // Ask the collation which section number the time zone belongs in, based on its locale name.
    NSInteger sectionNumber = [collation sectionForObject:timeZone collationStringSelector:@selector(localeName)];

I tried to do as in my piece of code

    NSInteger sectionNumber = [collation sectionForObject:completeClass collationStringSelector:@selector(idValue)];
where my app crashed saying 

    -[__NSArrayM idValue]: unrecognized selector sent to instance 0x95e4ee0


Where `completeClass` is an instance of `IDSetter` class in which `idValue` is a string value. In `IDSetter`, I am passing an array as in the apple's sample code, but with the difference the array is a complex one, where it has few strings and arrays of varying count
as objects in it. I am setting `idValue` from one of those objects(like, string `[firstArray objectAtIndex:x]` sometime and string at `[[secondArray objectAtIndex: y] objectAtIndex:x]` for some other time) depending on my needs and Im sure that setting `idValue` is void of any mistakes. In brief, I am trying to sort/group based on this `idValue` which in turn is set from the complex array.

Can some one point me my mistake in doing this and correct me so that I can do collation with my complex array. What should I correct to get this working? 

Thanks in advance.

  [1]: http://developer.apple.com/library/ios/#samplecode/TableViewSuite/Listings/1_SimpleTableView_Classes_RootViewController_m.html#//apple_ref/doc/uid/DTS40007318-1_SimpleTableView_Classes_RootViewController_m-DontLinkElementID_4