Update DiaBLa.py

DiaBLa.py

@@ -205,6 +205,6 @@ class Diabla(datasets.GeneratorBasedBuilder):
                     # add to history (without dialogue info and history)
                     minimal_utterance = utterance_instance.copy()
                     utterance_instance['dialogue_meta'] = dialogue_info
-                    utterance_instance['dialogue_history'] = dialogue_history
+                    utterance_instance['dialogue_history'] = dialogue_history.copy()
                     dialogue_history.append(minimal_utterance) 
                     yield id_, utterance_instance