Fix distiller.py (#12910)

* fix distiller

* fix style

examples/research_projects/distillation/distiller.py

@@ -380,21 +380,19 @@ class Distiller:
         lm_labels: `torch.tensor(bs, seq_length)` - The language modeling labels (mlm labels for MLM and clm labels for CLM).
         """
         if self.mlm:
-            s_logits, s_hidden_states = self.student(
+            student_outputs = self.student(
                 input_ids=input_ids, attention_mask=attention_mask
             )  # (bs, seq_length, voc_size)
             with torch.no_grad():
-                t_logits, t_hidden_states = self.teacher(
+                teacher_outputs = self.teacher(
                     input_ids=input_ids, attention_mask=attention_mask
                 )  # (bs, seq_length, voc_size)
         else:
-            s_logits, _, s_hidden_states = self.student(
-                input_ids=input_ids, attention_mask=None
-            )  # (bs, seq_length, voc_size)
+            student_outputs = self.student(input_ids=input_ids, attention_mask=None)  # (bs, seq_length, voc_size)
             with torch.no_grad():
-                t_logits, _, t_hidden_states = self.teacher(
-                    input_ids=input_ids, attention_mask=None
-                )  # (bs, seq_length, voc_size)
+                teacher_outputs = self.teacher(input_ids=input_ids, attention_mask=None)  # (bs, seq_length, voc_size)
+        s_logits, s_hidden_states = student_outputs["logits"], student_outputs["hidden_states"]
+        t_logits, t_hidden_states = teacher_outputs["logits"], teacher_outputs["hidden_states"]
         assert s_logits.size() == t_logits.size()
 
         # https://github.com/peterliht/knowledge-distillation-pytorch/blob/master/model/net.py#L100