Don't return duplicate base categories

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@3247 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5/Document/Amount.py

@@ -147,7 +147,12 @@ class Amount(Base, Variated):
       Return the list of base_category from all variation related to amount.
       It is maybe a nonsense, but useful for correcting user errors.
     """
-    return [x.split('/')[0] for x in self.getVariationCategoryList()]
+    base_category_list = []
+    for category in self.getVariationCategoryList():
+      base_category = category.split('/')[0]
+      if base_category not in base_category_list:
+        base_category_list.append(base_category)
+    return base_category_list
 
   security.declareProtected(Permissions.AccessContentsInformation, 'getVariationValue')
   def getVariationValue(self):