NSManagedObject and Comparable is the solution?

I need to compare two NSManagedObject objects to need if an object is inside in a array.
Extend NSmangedObject class or my custom subclass like Lemma, Kanji that are created by core data, could be the solution to compare two object?

example:
Lemma is subclass of NSManagedObject
var lemma1:Lemma
var lemma2:Lemma

if lemma1 == lemma2 {
print(“find”)
}else{
print(“Retry”)
}