Update TRAIN.md

TRAIN.md

@@ -1,3 +1,4 @@
+```python
 from datasets import interleave_datasets, load_dataset
 
 samsum_dataset = load_dataset("samsum", split="train")
@@ -76,4 +77,5 @@ trainer = Seq2SeqTrainer(
     compute_metrics=compute_metrics,
 )
 
-trainer.train()
+trainer.train()
+```