diff --git a/stcheck.py b/stcheck.py
index 2804e00243500e8a9e6358fcb4f9572d9b646565_c3RjaGVjay5weQ==..e2b17c6ac2773f1e734d92a671d90b297064b372_c3RjaGVjay5weQ== 100644
--- a/stcheck.py
+++ b/stcheck.py
@@ -156,7 +156,7 @@
                     errors.append('order column out of bound %s' % term.value)
         else:
             stmt = term.stmt
-            for tvref in term.iget_nodes(VariableRef):
+            for tvref in variable_refs(term):
                 for vref in tvref.variable.references():
                     if vref.relation() or vref in stmt.selection:
                         break