diff --git a/swh/web/api/views/utils.py b/swh/web/api/views/utils.py
--- a/swh/web/api/views/utils.py
+++ b/swh/web/api/views/utils.py
@@ -43,7 +43,7 @@
     if enrich_fn is None:
         enrich_fn = (lambda x: x)
     res = lookup_fn(*args)
-    if not res:
+    if res is None:
         raise NotFoundExc(notfound_msg)
     if isinstance(res, (map, list, GeneratorType)):
         return [enrich_fn(x) for x in res]