Fix bnb training test failure (#34414)

* Fix bnb training test: compatibility with OPTSdpaAttention

tests/quantization/bnb/test_4bit.py

@@ -29,6 +29,7 @@ from transformers import (
     BitsAndBytesConfig,
     pipeline,
 )
+from transformers.models.opt.modeling_opt import OPTAttention
 from transformers.testing_utils import (
     apply_skip_if_not_implemented,
     is_bitsandbytes_available,
@@ -565,7 +566,7 @@ class Bnb4BitTestTraining(Base4bitTest):
 
         # Step 2: add adapters
         for _, module in model.named_modules():
-            if "OPTAttention" in repr(type(module)):
+            if isinstance(module, OPTAttention):
                 module.q_proj = LoRALayer(module.q_proj, rank=16)
                 module.k_proj = LoRALayer(module.k_proj, rank=16)
                 module.v_proj = LoRALayer(module.v_proj, rank=16)