CoreDataClass *classObject = (CoreDataClass *)[some method that returns a dictionary with exact KVC pairs that match CoreDataClass];

NSString *myString = classObject.stringProperty;

CoreDataClass *classObject = (CoreDataClass *)[some method that returns a dictionary with exact KVC pairs that match CoreDataClass];
NSString *myString = [classObject valueForKey:@"stringProperty"];

+(CoreDataClass *) coreDataObjectWithDictionary:(NSDictionary *) spec {
  CoreDataClass *myInstance = [NSEntityDescription insertNewObjectForEntityForName: @"CoreDataClass" inManagedObjectContext: [myMOCProvider sharedMOC];
  myInstance.someProp = [spec valueForKey:@"someProp"];
}