diff --git a/.github/dependabot.yml b/.github/dependabot.yml
index 14f01789..ad77bd87 100644
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -8,4 +8,4 @@ updates:
   - package-ecosystem: "github-actions"
     directory: "/" # Location of package manifests
     schedule:
-      interval: "weekly"
+      interval: "monthly"
diff --git a/justfile b/justfile
index dfb914aa..d8abe8af 100644
--- a/justfile
+++ b/justfile
@@ -30,3 +30,12 @@ bump-dry part='patch':
 
 push:
     git push && git push --tags
+
+types:
+    uv run tox -e types
+
+lint:
+    uv run ruff check
+
+format:
+    uv run ruff format --diff
diff --git a/src/torchio/data/inference/aggregator.py b/src/torchio/data/inference/aggregator.py
index 7d8fdc07..80d9a9b5 100644
--- a/src/torchio/data/inference/aggregator.py
+++ b/src/torchio/data/inference/aggregator.py
@@ -104,7 +104,7 @@ def _initialize_avgmask_tensor(self, batch: torch.Tensor) -> None:
         )
 
     @staticmethod
-    def _get_hann_window(patch_size):
+    def _get_hann_window(patch_size) -> torch.Tensor:
         hann_window_3d = torch.as_tensor([1])
         # create a n-dim hann window
         for spatial_dim, size in enumerate(patch_size):
@@ -211,6 +211,7 @@ def add_batch(
                     j_ini:j_fin,
                     k_ini:k_fin,
                 ] += patch
+                assert self._hann_window is not None
                 self._avgmask_tensor[
                     :,
                     i_ini:i_fin,