diff --git a/prody/utilities/checkers.py b/prody/utilities/checkers.py
index 6ffdf4858..f0bfee887 100644
--- a/prody/utilities/checkers.py
+++ b/prody/utilities/checkers.py
@@ -136,4 +136,3 @@ def incr(n, i):
 
     return True
 
-A_CSETS_NDIMS = set([2, 6])