diff --git a/utils_nlp/models/transformers/abssum.py b/utils_nlp/models/transformers/abssum.py
index 80751c2..14ba566 100644
--- a/utils_nlp/models/transformers/abssum.py
+++ b/utils_nlp/models/transformers/abssum.py
@@ -9,6 +9,7 @@ from collections import namedtuple
 import itertools
 import logging
 import os
+import pickle
 import random
 
 import numpy as np
@@ -335,9 +336,9 @@ def validate(summarizer, validate_sum_dataset, cache_dir):
     TOP_N = 8
 
     src = validate_sum_dataset.source[0:TOP_N]
-    reference_summaries = ["".join(t).rstrip("\n") for t in validate_sum_dataset.target[0:TOP_N]]
+    reference_summaries = [" ".join(t).rstrip("\n") for t in validate_sum_dataset.target[0:TOP_N]]
     generated_summaries = summarizer.predict(
-        shorten_dataset(validate_sum_dataset, top_n=TOP_N), num_gpus=2, batch_size=4
+        shorten_dataset(validate_sum_dataset, top_n=TOP_N), num_gpus=1, batch_size=4
     )
     assert len(generated_summaries) == len(reference_summaries)
     for i in generated_summaries[0:1]: