diff --git a/swh/lister/gitlab/tests/test_lister.py b/swh/lister/gitlab/tests/test_lister.py
index 5b8096360366f57fd3d2e7ca84a6865b861cef5c..d1fd7971f6014e2956145d1cc3bdc26f4e2ec98b 100644
--- a/swh/lister/gitlab/tests/test_lister.py
+++ b/swh/lister/gitlab/tests/test_lister.py
@@ -96,7 +96,7 @@ def test_lister_gitlab_heptapod(datadir, swh_scheduler, requests_mock):
 def gitlab_page_response(datadir, instance: str, id_after: int) -> List[Dict]:
     """Return list of repositories (out of test dataset)"""
     datapath = Path(datadir, f"https_{instance}", f"api_response_page{id_after}.json")
-    return json.loads(datapath.read_text()) if datapath.exists else []
+    return json.loads(datapath.read_text()) if datapath.exists() else []
 
 
 def test_lister_gitlab_with_pages(swh_scheduler, requests_mock, datadir):
diff --git a/swh/lister/maven/lister.py b/swh/lister/maven/lister.py
index a7bb79f2c7727b745723f98c987e19311681055a..0da9b6519d618d9b8c22320e9a85ff40aac84060 100644
--- a/swh/lister/maven/lister.py
+++ b/swh/lister/maven/lister.py
@@ -58,7 +58,7 @@ class MavenLister(Lister[MavenListerState, RepoPage]):
         self,
         scheduler: SchedulerInterface,
         url: str,
-        index_url: str = None,
+        index_url: str,
         instance: Optional[str] = None,
         credentials: CredentialsType = None,
         max_origins_per_page: Optional[int] = None,
diff --git a/swh/lister/nixguix/tests/test_lister.py b/swh/lister/nixguix/tests/test_lister.py
index a00a5f6186b8bc32a6ca146dc012a5f9297bf087..209bc5aa79571003418b22e841b9cf5952891bc5 100644
--- a/swh/lister/nixguix/tests/test_lister.py
+++ b/swh/lister/nixguix/tests/test_lister.py
@@ -44,7 +44,7 @@ SOURCES = {
 def page_response(datadir, instance: str = "success") -> List[Dict]:
     """Return list of repositories (out of test dataset)"""
     datapath = Path(datadir, f"sources-{instance}.json")
-    return json.loads(datapath.read_text()) if datapath.exists else []
+    return json.loads(datapath.read_text()) if datapath.exists() else []
 
 
 @pytest.mark.parametrize(
diff --git a/tox.ini b/tox.ini
index c9a8843906a3844b21f517f5b099756145eff232..83ee868a40fb9b0fe264650a99c522d9f0bb580c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -38,7 +38,7 @@ commands =
 extras =
   testing
 deps =
-  mypy==0.942
+  mypy==1.0.1
 commands =
   mypy swh