Modernize cleanups

loopy/isl_helpers.py

 """isl helpers"""
 
-from __future__ import division
-from __future__ import absolute_import
-from six.moves import range
-from six.moves import zip
+from __future__ import division, absolute_import
 
 __copyright__ = "Copyright (C) 2012 Andreas Kloeckner"
 
@@ -28,6 +25,10 @@ THE SOFTWARE.
 """
 
 
+from six.moves import range, zip
+
+from loopy.diagnostic import StaticValueFindingError
+
 import islpy as isl
 from islpy import dim_type