wi_ids = self.pool.get('marketing.campaign.workitem').search(cr, uid,
[('segment_id.campaign_id', '=', ca_obj.campaign_id.id)])
total_cost = ca_obj.activity_id.variable_cost + \
- (ca_obj.campaign_id.fixed_cost / len(wi_ids))
+ ((ca_obj.campaign_id.fixed_cost or 0.00) / len(wi_ids))
result[ca_obj.id] = total_cost
return result
_columns = {