diff --git a/src/moscot/_types.py b/src/moscot/_types.py
index 3d463c851..024471886 100644
--- a/src/moscot/_types.py
+++ b/src/moscot/_types.py
@@ -8,7 +8,7 @@
 try:
     from numpy.typing import DTypeLike, NDArray
 
-    ArrayLike = NDArray[np.float_]
+    ArrayLike = NDArray[np.float64]
 except (ImportError, TypeError):
     ArrayLike = np.ndarray  # type: ignore[misc]
     DTypeLike = np.dtype  # type: ignore[misc]
diff --git a/src/moscot/problems/_utils.py b/src/moscot/problems/_utils.py
index b2d2658e2..90bbe7aa7 100644
--- a/src/moscot/problems/_utils.py
+++ b/src/moscot/problems/_utils.py
@@ -37,7 +37,7 @@ def handle_joint_attr(
 
         # if this is True we have custom cost matrix or moscot cost - in this case we have a custom cost matrix
         if joint_attr.get("tag", None) == "cost_matrix" and (
-            len(joint_attr) == 2 or kwargs.get("attr", None) == "obsp"
+            len(joint_attr) == 2 or kwargs.get("attr") == "obsp"
         ):
             joint_attr.setdefault("cost", "custom")
             joint_attr.setdefault("attr", "obsp")
diff --git a/src/moscot/problems/cross_modality/_mixins.py b/src/moscot/problems/cross_modality/_mixins.py
index 5c2377e19..5a3967e1f 100644
--- a/src/moscot/problems/cross_modality/_mixins.py
+++ b/src/moscot/problems/cross_modality/_mixins.py
@@ -80,7 +80,7 @@ def _get_features(
             attr: Dict[str, Any],
         ) -> ArrayLike:
             data = getattr(adata, attr["attr"])
-            key = attr.get("key", None)
+            key = attr.get("key")
             return data if key is None else data[key]
 
         if self._src_attr is None: