Update brainglobe_atlasapi/atlas_generation/atlas_scripts/example_mou…

…se.py

Co-authored-by: Alessandro Felder <alessandrofelder@users.noreply.github.com>

brainglobe_atlasapi/atlas_generation/atlas_scripts/example_mouse.py

@@ -50,12 +50,7 @@ def retrieve_reference_and_annotation():
 
 def retrieve_hemisphere_map():
     """
-    Retrieve a hemisphere map for the atlas.
-
-    If your atlas is asymmetrical, you may want to use a hemisphere map. This is an array in the same shape as your template,
-    with 0's marking the left hemisphere, and 1's marking the right.
-
-    If your atlas is symmetrical, ignore this function.
+The Allen atlas is symmetrical, so we can just return `None` in this function.
 
     Returns:
         numpy.array or None: A numpy array representing the hemisphere map, or None if the atlas is symmetrical.