diff --git a/modules/purchase_trade/stock.py b/modules/purchase_trade/stock.py
index 2f6a1d4..5ead2a6 100755
--- a/modules/purchase_trade/stock.py
+++ b/modules/purchase_trade/stock.py
@@ -502,7 +502,7 @@ class CharterCondition(ModelSQL, ModelView):
         'purchase.line', "Purchase Line", ondelete='CASCADE')
     party = fields.Many2One('party.party', "Party")
     party_role = fields.Selection(
-        'get_party_roles', "Party Role")
+        _party_role_selection, "Party Role")
     responsibility = fields.Selection([
         (None, ''),
         ('ours', 'Ours'),