diff --git a/reformer.py b/reformer.py
index a9d088b..cdbcd03 100644
--- a/reformer.py
+++ b/reformer.py
@@ -83,7 +83,7 @@ def gen_validation_inputs(n_devices):
         # different validation each time but consistent across the run
     ids = next(gen_inputs(n_devices))
     while True:
-        return ids
+        yield ids
 
 
 def create_fixed_training_schedule(lr):
diff --git a/requirements-colab.txt b/requirements-colab.txt
index 63a2536..188b626 100644
--- a/requirements-colab.txt
+++ b/requirements-colab.txt
@@ -1,4 +1,5 @@
 jax
 jaxlib
 git+https://github.com/google/trax.git@v1.2.2
-tokenizers
\ No newline at end of file
+tokenizers
+gin
\ No newline at end of file