human
Solve the following python programming problem given the following code:
def _keypair_db_call_stubs(self) : 
    def db_key_pair_get_all_by_user(context, user_id) : 
        return [dict (test_keypair.fake_keypair, name = self.existing_key_name, public_key = self.pub_key, fingerprint = self.fingerprint)] 
def db_key_pair_create(context, keypair) : 
        return dict (test_keypair.fake_keypair, ** keypair) 
def db_key_pair_destroy(context, user_id, name) : 
        if (name == self.existing_key_name) : 
            self.key_destroyed = True 
def db_key_pair_get(context, user_id, name) : 
        if ((name == self.existing_key_name) and (not self.key_destroyed)) : 
            return dict (test_keypair.fake_keypair, name = self.existing_key_name, public_key = self.pub_key, fingerprint = self.fingerprint) 
else : 
            raise exception.KeypairNotFound (user_id = user_id, name = name) 
self.stub_out ('nova.db.key_pair_get_all_by_user', db_key_pair_get_all_by_user) 
    self.stub_out ('nova.db.key_pair_create', db_key_pair_create) 
    self.stub_out ('nova.db.key_pair_destroy', <MASK>) 
    self.stub_out ('nova.db.key_pair_get', db_key_pair_get) 
    
    Given the code above, what is a proper replacement for <MASK>? Choose among: db_key_pair_get_all_by_user, db_key_pair_get, db_key_pair_create, self
assistant
#Here is Python code to print = self.
def db_key_pair_destroy(