diff --git a/swh/web/api/views/utils.py b/swh/web/api/views/utils.py
index 3d8e1374..583cf3f7 100644
--- a/swh/web/api/views/utils.py
+++ b/swh/web/api/views/utils.py
@@ -1,73 +1,73 @@
 # Copyright (C) 2015-2018  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU Affero General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 from rest_framework.response import Response
 from rest_framework.decorators import api_view
 
 from types import GeneratorType
 
 from swh.web.common.exc import NotFoundExc
 from swh.web.api.apiurls import APIUrls, api_route
 
 
 def api_lookup(lookup_fn, *args,
                notfound_msg='Object not found',
                enrich_fn=None):
     """
     Capture a redundant behavior of:
         - looking up the backend with a criteria (be it an identifier or
           checksum) passed to the function lookup_fn
         - if nothing is found, raise an NotFoundExc exception with error
           message notfound_msg.
         - Otherwise if something is returned:
             - either as list, map or generator, map the enrich_fn function to
               it and return the resulting data structure as list.
             - either as dict and pass to enrich_fn and return the dict
               enriched.
 
     Args:
         - lookup_fn: function expects one criteria and optional supplementary
           \*args.
         - notfound_msg: if nothing matching the criteria is found,
           raise NotFoundExc with this error message.
         - enrich_fn: Function to use to enrich the result returned by
           lookup_fn. Default to the identity function if not provided.
         - \*args: supplementary arguments to pass to lookup_fn.
 
     Raises:
         NotFoundExp or whatever `lookup_fn` raises.
 
     """ # noqa
     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]
     return enrich_fn(res)
 
 
 @api_view(['GET', 'HEAD'])
 def api_home(request):
     return Response({}, template_name='api/api.html')
 
 
 APIUrls.add_url_pattern(r'^$', api_home, view_name='api-homepage')
 
 
 @api_route(r'/', 'api-endpoints')
 def api_endpoints(request):
     """Display the list of opened api endpoints.
 
     """
     routes = APIUrls.get_app_endpoints().copy()
     for route, doc in routes.items():
         doc['doc_intro'] = doc['docstring'].split('\n\n')[0]
     # Return a list of routes with consistent ordering
     env = {
         'doc_routes': sorted(routes.items())
     }
     return Response(env, template_name="api/endpoints.html")