fix class assign visitor. visit targets instead of the node

Author: vindex10

python/asthelper.py

@@ -52,7 +52,7 @@ def __init__(self, instance_name):
     def visit_Assign(self, node):
         ac = AttributeCollector(self.instance_name)
         for target in node.targets:
-            ac.visit(node)
+            ac.visit(target)
         self.attributes |= ac.data