diff --git a/requirements.txt b/requirements.txt
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,4 @@
-dateutil
+python-dateutil
 psycopg2
 vcversioner
 
diff --git a/swh/storage/tests/test_storage.py b/swh/storage/tests/test_storage.py
--- a/swh/storage/tests/test_storage.py
+++ b/swh/storage/tests/test_storage.py
@@ -1199,7 +1199,8 @@
             'visit': origin_visit2['visit'],
             'target': self.revision3['id'],
         })
-        # 2 occurrences on same revision with lower validity date with 1 day delta
+        # 2 occurrences on same revision with lower validity date with 1 day
+        # delta
         self.storage.occurrence_add([occurrence2])
         self.storage.occurrence_add([occurrence3])