[`BC`] Fix BC for other libraries (#29934)

* fi xbc?

* nit

src/transformers/models/cohere/modeling_cohere.py

@@ -1139,7 +1139,7 @@ class CohereForCausalLM(CoherePreTrainedModel):
         # TODO joao: standardize interface for the different Cache classes and remove of this if
         has_static_cache = False
         if past_key_values is None:
-            past_key_values = getattr(self.model.layers[0].self_attn, "past_key_value", None)
+            past_key_values = getattr(getattr(self.model.layers[0], "self_attn", {}), "past_key_value", None)
             has_static_cache = past_key_values is not None
 
         past_length = 0

src/transformers/models/gemma/modeling_gemma.py

@@ -1143,7 +1143,7 @@ class GemmaForCausalLM(GemmaPreTrainedModel):
         # TODO joao: standardize interface for the different Cache classes and remove of this if
         has_static_cache = False
         if past_key_values is None:
-            past_key_values = getattr(self.model.layers[0].self_attn, "past_key_value", None)
+            past_key_values = getattr(getattr(self.model.layers[0], "self_attn", {}), "past_key_value", None)
             has_static_cache = past_key_values is not None
 
         past_length = 0

src/transformers/models/llama/modeling_llama.py

@@ -1240,7 +1240,7 @@ class LlamaForCausalLM(LlamaPreTrainedModel):
         # TODO joao: standardize interface for the different Cache classes and remove of this if
         has_static_cache = False
         if past_key_values is None:
-            past_key_values = getattr(self.model.layers[0].self_attn, "past_key_value", None)
+            past_key_values = getattr(getattr(self.model.layers[0], "self_attn", {}), "past_key_value", None)
             has_static_cache = past_key_values is not None
 
         past_length = 0