Cómo crear métodos mágicos en Objective C

I am trying to develop a set of magic findByX methods in a generic Model class that eventually will issue queries to Core Data using NSPredicate objetos:

• (id)findByName;
• (id)findByCreated;
• ...

Following advice from a pregunta SO anterior I can intercept messages that request non-existent methods by overriding resolveInstanceMethod:

#include <objc/runtime.h>

+ (BOOL) resolveInstanceMethod:(SEL)aSel {
  if (aSel == @selector(resolveThisMethodDynamically)) {
    class_addMethod([self class], aSel, (IMP) dynamicMethodIMP, "v@:");
    return YES;
  }
  return [super resolveInstanceMethod:aSel];
}

void dynamicMethodIMP(id self, SEL _cmd) {
  NSLog(@"Voilà");
}

Sin embargo, cuando trato de usar [myObject resolveThisMethodDynamically] the compiler raises the following error:

"No visible @interface for 'MyModel' declares the selector 'resolveThisMethodDynamically'"

which makes sense, since there isn't any declaration of that method. So, what am I missing here? Is there any best practice to accomplish this?

¡Gracias!