diff --git a/product/ERP5/Document/SupplyLine.py b/product/ERP5/Document/SupplyLine.py
index f7ce31887100bd525309459e3dc78bb92d9f914f..ea00f73441375b946f4c3f0f1a60c6a02be8f1ef 100644
--- a/product/ERP5/Document/SupplyLine.py
+++ b/product/ERP5/Document/SupplyLine.py
@@ -31,11 +31,12 @@ from AccessControl import ClassSecurityInfo
 from Products.ERP5Type import Permissions, PropertySheet
 from Products.ERP5Type.Accessor.Constant import PropertyGetter as ConstantGetter
 from Products.ERP5Type.XMLMatrix import XMLMatrix
+from Products.ERP5.Document.Amount import Amount
 from Products.ERP5.Document.Path import Path
 from Products.ERP5Type.Utils import convertToUpperCase
 
 
-class SupplyLine(Path, XMLMatrix):
+class SupplyLine(Path, Amount, XMLMatrix):
     """A Supply Line is a path to define price 
     """