Update comments mentioning Python 2.

examples/mm-imdb/run_mmimdb.py

@@ -164,7 +164,7 @@ def train(args, train_dataset, model, tokenizer, criterion):
     best_f1, n_no_improve = 0, 0
     model.zero_grad()
     train_iterator = trange(int(args.num_train_epochs), desc="Epoch", disable=args.local_rank not in [-1, 0])
-    set_seed(args)  # Added here for reproductibility (even between python 2 and 3)
+    set_seed(args)  # Added here for reproductibility
     for _ in train_iterator:
         epoch_iterator = tqdm(train_dataloader, desc="Iteration", disable=args.local_rank not in [-1, 0])
         for step, batch in enumerate(epoch_iterator):