core data simple fetch request template - core-data

Question

I have a small core data base "Guests" and I am trying to get the results from a fetch request template called FetchRequestA, I made a button to trigger in the console the results from the request but I keep on getting a null answer, the request is set to display all guestlastnames that contain a d ? here is the code that i am using :
- (IBAction)fetchA:(id)sender {
NSFetchRequest *request2 = [[[self managedObjectModel] fetchRequestTemplateForName:#"FetchRequestA"] copy];
NSSortDescriptor *sort = [[NSSortDescriptor alloc]initWithKey:#"guestlastname" ascending:YES];
[request2 setSortDescriptors:[NSArray arrayWithObject:sort]];
NSArray *sortDescriptors = [[NSArray alloc]initWithObjects:sort, nil];
[request2 setSortDescriptors:sortDescriptors];
NSError *error = nil;
NSArray *fetchedObjects = [[self managedObjectContext] executeFetchRequest:request2 error:&error];
if (fetchedObjects == nil) {
NSLog(#"problem %#", error);
}
for (Guests *guestlastname in fetchedObjects) {
NSLog(#"Fetched Object = %#", guestlastname.guestlastname);
}
}
Am I missing a method ? have perused around but to no avail, thanks in advance.

Answer 1

Here is solution :
(IBAction)gettemplatebutton:(id)sender {
AppDelegate *appDelegate = [[UIApplication sharedApplication] delegate];
NSManagedObjectContext *context = [appDelegate managedObjectContext];
NSManagedObjectModel* model = [[context persistentStoreCoordinator] managedObjectModel];
NSDictionary* dict = [[NSDictionary alloc]initWithObjectsAndKeys: self.fetchedObjects, #"guestlastname",nil];
NSFetchRequest* request2 = [model fetchRequestFromTemplateWithName:#"FetchRequestA" substitutionVariables: dict];
NSError* error = nil;
NSArray *Guests2 = [context executeFetchRequest:request2 error:&error];
NSString *g3 = #"";
for(NSManagedObject *guestlastname in Guests2)
{
g3 = [g3 stringByAppendingString:[NSString stringWithFormat:#"%#\n", [guestlastname valueForKey:#"guestlastname"]]];
}
self.displaytemplateLabel.text = g3;
[_displaytemplateLabel setNumberOfLines:0];
for (NSManagedObject *guestlastname in Guests2)
{
{
NSLog(#"%#", [guestlastname valueForKey:#"guestlastname"]);
}
}
}
and added #property (nonatomic, retain) NSArray *fetchedObjects; in header file.