From fbe11fe7d92d65eafa9e856c927900897b99f998 Mon Sep 17 00:00:00 2001
From: otioss <otioss@protonmail.com>
Date: Wed, 22 Jun 2022 21:15:53 +0700
Subject: [PATCH] Fixes issue #1868 regarding TypeError: ZipperIterDataPipe
 instance doesn't have a valid length

---
 beginner_source/translation_transformer.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/beginner_source/translation_transformer.py b/beginner_source/translation_transformer.py
index 345f31f05c1..083fcc6ed30 100644
--- a/beginner_source/translation_transformer.py
+++ b/beginner_source/translation_transformer.py
@@ -303,7 +303,7 @@ def train_epoch(model, optimizer):
         optimizer.step()
         losses += loss.item()
 
-    return losses / len(train_dataloader)
+    return losses / len(list(train_dataloader))
 
 
 def evaluate(model):
@@ -327,7 +327,7 @@ def evaluate(model):
         loss = loss_fn(logits.reshape(-1, logits.shape[-1]), tgt_out.reshape(-1))
         losses += loss.item()
 
-    return losses / len(val_dataloader)
+    return losses / len(list(val_dataloader))
 
 ######################################################################
 # Now we have all the ingredients to train our model. Let's do it!