fix CausalLM

modeling_ltgbert.py

@@ -528,7 +528,7 @@ class LtgbertForCausalLM(LtgbertModel):
             )
             return ((masked_lm_loss,) + output) if masked_lm_loss is not None else output
 
-        return MaskedLMOutput(
+        return CausalLMOutput(
             loss=masked_lm_loss,
             logits=subword_prediction,
             hidden_states=contextualized_embeddings if output_hidden_states else None,