1#import <Foundation/Foundation.h> 2#import "NSObject+Custom.h" 3 4@implementation NSObject (Custom) 5 6- (void)methodIsAbstract:(SEL)selector; 7{ 8 [NSException raise:NSInternalInconsistencyException 9 format:@"*** No concrete implementation for selector '%@' in class %@. Abstract definition must be overriden.", 10 NSStringFromSelector(selector), NSStringFromClass(isa)]; 11} 12 13@end 14