diff --git a/modules/purchase_trade/purchase.py b/modules/purchase_trade/purchase.py
index de81f5b..4f9cc46 100755
--- a/modules/purchase_trade/purchase.py
+++ b/modules/purchase_trade/purchase.py
@@ -509,7 +509,7 @@ class Line(metaclass=PoolMeta):
     
     @fields.depends('product')
     def on_change_with_attribute_set(self, name=None):
-        if self.product and self.product.template:
+        if self.product and self.product.template and self.product.template.attribute_set:
             return self.product.template.attribute_set.id
 
     @fields.depends('product', 'attributes')