diff --git a/hepdata_validator/schema_downloader.py b/hepdata_validator/schema_downloader.py
index ca45c83..a777e29 100644
--- a/hepdata_validator/schema_downloader.py
+++ b/hepdata_validator/schema_downloader.py
@@ -114,11 +114,18 @@ def save_locally(self, schema_name, schema_spec, overwrite=False):
         """
 
         file_path = os.path.join(self.saved_schema_path, schema_name)
+        file_folder = os.path.dirname(file_path)
 
         # Skip download if the file exist
         if os.path.isfile(file_path) and not overwrite:
             return
 
-        os.makedirs(os.path.dirname(file_path), exist_ok=True)
+        # This is compatible both with Python2 and Python3
+        try:
+            os.makedirs(file_folder)
+        except OSError:
+            if not os.path.isdir(file_folder):
+                raise
+
         with open(file_path, 'w') as f:
             f.write(schema_spec)
diff --git a/setup.py b/setup.py
index 1cd9a6c..18e1a04 100644
--- a/setup.py
+++ b/setup.py
@@ -13,6 +13,7 @@
     'pytest-cov>=1.8.0',
     'pytest-pep8>=1.0.6',
     'coverage>=3.7.1',
+    'mock>=2.0.0',
 ]
 
 extras_require = {
diff --git a/testsuite/test_schema_downloader.py b/testsuite/test_schema_downloader.py
index 2a45dfa..e161467 100644
--- a/testsuite/test_schema_downloader.py
+++ b/testsuite/test_schema_downloader.py
@@ -2,7 +2,7 @@
 import pytest
 from hepdata_validator.schema_downloader import HTTPSchemaDownloader
 from requests.exceptions import HTTPError
-from unittest.mock import patch
+from mock import patch
 
 
 ####################################################