diff --git a/python/damask/_Lambert.py b/python/damask/_Lambert.py
index 0ff177f9b..3524d3567 100644
--- a/python/damask/_Lambert.py
+++ b/python/damask/_Lambert.py
@@ -36,7 +36,7 @@ sc   = np.pi**(1./6.)/6.**(1./6.)
 beta = np.pi**(5./6.)/6.**(1./6.)/2.
 R1   = (3.*np.pi/4.)**(1./3.)
 
-def CubeToBall(cube):
+def cube_to_ball(cube):
     """
     Map a point in a uniform refinable cubical grid to a point on a uniform refinable grid on a ball.
 
@@ -87,7 +87,7 @@ def CubeToBall(cube):
     return ball
 
 
-def BallToCube(ball):
+def ball_to_cube(ball):
     """
     Map a point on a uniform refinable grid on a ball to a point in a uniform refinable cubical grid.
 
diff --git a/python/damask/rotation.py b/python/damask/rotation.py
index 8cb1f139d..0b481e149 100644
--- a/python/damask/rotation.py
+++ b/python/damask/rotation.py
@@ -1,6 +1,6 @@
 import numpy as np
 
-from ._Lambert import *
+from ._Lambert import ball_to_cube, cube_to_ball
 
 P = -1
 
@@ -802,7 +802,7 @@ class Rotation:
     @staticmethod
     def ho2cu(ho):
         """Homochoric vector to cubochoric vector."""
-        return BallToCube(ho)
+        return ball_to_cube(ho)
 
 
     #---------- Cubochoric ----------
@@ -834,4 +834,4 @@ class Rotation:
     @staticmethod
     def cu2ho(cu):
         """Cubochoric vector to homochoric vector."""
-        return CubeToBall(cu)
+        return cube_to_ball(cu)