diff --git a/surface_distance/metrics.py b/surface_distance/metrics.py
index 7aa12b1..427812a 100644
--- a/surface_distance/metrics.py
+++ b/surface_distance/metrics.py
@@ -99,7 +99,7 @@ def _crop_to_bounding_box(mask, bbox_min, bbox_max):
   # we need to zeropad the cropped region with 1 voxel at the lower,
   # the right (and the back on 3D) sides. This is required to obtain the
   # "full" convolution result with the 2x2 (or 2x2x2 in 3D) kernel.
-  TODO:  This is correct only if the object is interior to the
+  # TODO:  This is correct only if the object is interior to the
   # bounding box.
   cropmask = np.zeros((bbox_max - bbox_min) + 2, np.uint8)