diff --git a/chunkflow/volume.py b/chunkflow/volume.py
index 5b8d56ea..8b5fc82d 100644
--- a/chunkflow/volume.py
+++ b/chunkflow/volume.py
@@ -9,7 +9,8 @@
 
 from cloudvolume import CloudVolume
 from chunkflow.lib.utils import str_to_dict
-from .lib.cartesian_coordinate import BoundingBox, Cartesian, BoundingBoxes, PhysicalBoudingBox
+from .lib.cartesian_coordinate import \
+    BoundingBox, Cartesian, BoundingBoxes, PhysicalBoudingBox
 from .chunk import Chunk
 
 
@@ -109,7 +110,8 @@ def block_size(self):
 
     @cached_property 
     def physical_bounding_box(self) -> PhysicalBoudingBox:
-        return PhysicalBoundingBox(self.start, self.stop, self.voxel_size)
+        return PhysicalBoudingBox(
+            self.start, self.stop, self.voxel_size)
 
     @cached_property
     def block_bounding_boxes(self) -> BoundingBoxes: