diff --git a/python_arborist.py b/python_arborist.py
index 2291c8a7931fba5d4b94412f1ec3870369235513..cdf3c1ec6689ee839145bc4eb2f7ccc9443721e5 100644
--- a/python_arborist.py
+++ b/python_arborist.py
@@ -298,7 +298,9 @@ list_of_terminals    = [INTEGER, ADDOP, MULTOP, OPENPAREN, CLOSEPAREN]
 
 z = CFGBoltzmann.CFGBoltzmann(rules, list_of_nonterminals, list_of_terminals)
 cooked_rules = z.preprocessor()
-parse_me =  z.Gzero_shimmed(EXPRESSION, 3)
+bgen = z.Gzero_shimmed(EXPRESSION, 3)
+parse_me =  bgen[0]
+
 parse_me.append(ENDOFPARSE)