diff --git a/vskernels/kernels/placebo.py b/vskernels/kernels/placebo.py
index 13794d4..0dd24d3 100644
--- a/vskernels/kernels/placebo.py
+++ b/vskernels/kernels/placebo.py
@@ -4,9 +4,9 @@
 from typing import Any, Callable
 
 from stgpytools import inject_kwargs_params
-from vstools import Transfer, TransferT, core, fallback, inject_self, vs
+from vstools import core, fallback, inject_self, vs
 
-from ..types import Center, LeftShift, Slope, TopShift
+from ..types import LeftShift, TopShift
 from .complex import LinearScaler
 
 __all__ = [
diff --git a/vskernels/util.py b/vskernels/util.py
index e5eea28..e09d9be 100644
--- a/vskernels/util.py
+++ b/vskernels/util.py
@@ -119,9 +119,7 @@ class excluded_kernels(list[type]):
     def __init__(self) -> None:
         super().__init__(abstract_kernels)
 
-        self.exclude_sub = [
-            NoShiftBase, NoScaleBase, BicubicAuto
-        ]
+        self.exclude_sub = [NoShiftBase, NoScaleBase, BicubicAuto]
 
     def __contains__(self, key: object) -> bool:
         if not isinstance(key, type):