issue while executing script

# past_key_values_length
   1360 past_key_values_length = (
-> 1361     past_key_values[0][0].shape[2] if past_key_values is not None else 0
   1362 )
   1364 if inputs_embeds is None:
   1365     inputs_embeds = self.embed_tokens(input_ids) * self.embed_scale

AttributeError: 'NoneType' object has no attribute 'shape'