diff --git a/swh/web/common/service.py b/swh/web/common/service.py
--- a/swh/web/common/service.py
+++ b/swh/web/common/service.py
@@ -31,10 +31,10 @@
 MAX_LIMIT = 50  # Top limit the users can ask for
 
 
-def _first_element(l):
+def _first_element(lst):
     """Returns the first element in the provided list or None
     if it is empty or None"""
-    return next(iter(l or []), None)
+    return next(iter(lst or []), None)
 
 
 def lookup_multiple_hashes(hashes):
diff --git a/swh/web/tests/auth/test_api_auth.py b/swh/web/tests/auth/test_api_auth.py
--- a/swh/web/tests/auth/test_api_auth.py
+++ b/swh/web/tests/auth/test_api_auth.py
@@ -82,7 +82,7 @@
 
     # check for failed authentication when token format is invalid
     mock_keycloak(mocker)
-    api_client.credentials(HTTP_AUTHORIZATION=f"Bearer invalid-token-format")
+    api_client.credentials(HTTP_AUTHORIZATION="Bearer invalid-token-format")
 
     response = api_client.get(url)
     request = response.wsgi_request
@@ -106,7 +106,7 @@
     assert isinstance(request.user, AnonymousUser)
 
     # invalid authorization type
-    api_client.credentials(HTTP_AUTHORIZATION=f"Foo token")
+    api_client.credentials(HTTP_AUTHORIZATION="Foo token")
 
     response = api_client.get(url)
     request = response.wsgi_request
diff --git a/swh/web/tests/auth/test_backends.py b/swh/web/tests/auth/test_backends.py
--- a/swh/web/tests/auth/test_backends.py
+++ b/swh/web/tests/auth/test_backends.py
@@ -121,7 +121,7 @@
     mock_keycloak(mocker)
 
     request = api_request_factory.get(
-        url, HTTP_AUTHORIZATION=f"Bearer invalid-token-format"
+        url, HTTP_AUTHORIZATION="Bearer invalid-token-format"
     )
 
     with pytest.raises(AuthenticationFailed):
@@ -136,7 +136,7 @@
     access_token = sample_data.oidc_profile["access_token"]
 
     # Invalid authorization type
-    request = api_request_factory.get(url, HTTP_AUTHORIZATION=f"Foo token")
+    request = api_request_factory.get(url, HTTP_AUTHORIZATION="Foo token")
 
     with pytest.raises(AuthenticationFailed):
         drf_auth_backend.authenticate(request)
diff --git a/swh/web/tests/browse/views/test_origin.py b/swh/web/tests/browse/views/test_origin.py
--- a/swh/web/tests/browse/views/test_origin.py
+++ b/swh/web/tests/browse/views/test_origin.py
@@ -672,7 +672,7 @@
         "origin": origin["url"],
         "visit": get_swh_persistent_id(SNAPSHOT, snapshot["id"]),
         "anchor": get_swh_persistent_id(RELEASE, release_data["id"]),
-        "path": f"/",
+        "path": "/",
     }
 
     swh_dir_id = get_swh_persistent_id(