diff --git a/pytransform3d/rotations/_constants.py b/pytransform3d/rotations/_constants.py
index 7fbb092c9..dbab64a58 100644
--- a/pytransform3d/rotations/_constants.py
+++ b/pytransform3d/rotations/_constants.py
@@ -16,4 +16,5 @@
 
 eps = 1e-7
 
-two_pi = 2.0 * np.pi
\ No newline at end of file
+two_pi = 2.0 * np.pi
+