Problems accessing 1:N relationship in entity - core-data

Question

https://github.com/lokming/QuestionBank
I have entities: Bank,Section,Subsection,Set,Question.
I am having problems accessing relationship "NSSet Subsection" in entity Section and getting the message "[UITableViewCell thesubsection]: unrecognized selector sent to instance" from this code
in CRSectionVC.m which fills a tableview cell
- (NSArray *)allQuestions
{
NSSortDescriptor *division = [NSSortDescriptor sortDescriptorWithKey:#"subdivision" ascending:YES];
return [_section2.thesubsection sortedArrayUsingDescriptors:#[division]];
}
I can however access the "NNSet section" relationship in Bank entity using this code
NSSortDescriptor *division2 = [NSSortDescriptor sortDescriptorWithKey:#"division" ascending:YES];
return [self.detailItem2.thesection sortedArrayUsingDescriptors:#[division2]];
_section2 is declared in CRSubsectionVC.h
#property (strong, nonatomic) Section *section2;
The storyboard is
1. CRMasterViewController which displays ‘category’ attribute from Bank entity into a tableview,
Bank.h
#class Section;
#interface Bank : NSManagedObject
#property (nonatomic, retain) NSString * category;
#property (nonatomic, retain) NSSet *thesection;
#end
Bank.m
#implementation Bank
#dynamic category;
#dynamic thesection;
#end
When I tap a ‘category’ I segue and pass a Bank object to CRDetailViewController. I use following code:
NSSortDescriptor *division2 = [NSSortDescriptor sortDescriptorWithKey:#"division" ascending:YES];
return [self.detailItem2.thesection sortedArrayUsingDescriptors:#[division2]];
to fetch section relationship (NSSet *thesection) ‘division’ attribute from Bank into tableview.
Section.h
#class Bank, Subsection;
#interface Section : NSManagedObject
#property (nonatomic, retain) NSString * division;
#property (nonatomic, retain) Bank *bank;
#property (nonatomic, retain) NSSet *thesubsection;
#end
Section.m
#implementation Section
#dynamic division;
#dynamic bank;
#dynamic thesubsection;
#end
If I tap a ‘section’ ’ I segue and pass a Section object to CRSubsectionVC named _section2. When I try to access NSSet *thesubsection to get ‘subdivision’ attribute using code
NSSortDescriptor *division = [NSSortDescriptor sortDescriptorWithKey:#"subdivision"ascending:YES];
return [_section2.thesubsection sortedArrayUsingDescriptors:#[division]];
I get the error [UITableViewCell thesubsection]: unrecognized selector sent to instance. I cannot figure out why automated accessor ‘thesection’ works OK but not ‘thesubsection’ .
Subsection.h
#class Section, Set;
#interface Subsection : NSManagedObject
#property (nonatomic, retain) NSString * subdivision;
#property (nonatomic, retain) Section *section2;
#property (nonatomic, retain) NSSet *set;
#end
Subsection.m
#implementation Subsection
#dynamic subdivision;
#dynamic section2;
#dynamic set;
#end

Answer 1

Fixed the problem. A case of not copying code exactly from working template and understanding core data and table views.