I want to get the latest date of intervention of a centre in a new field named "intervention_id" in a "centre" form view which is related to another menuitem named intervention that shows every centre's dates of interventions(maintenance of equipements in each center),these 2 classes are of course related with relational fields so I tried this function :

def _get_latest_intervention(self, cr, uid, ids, field_name, args, context=None):
        res = {}
        obj_intervention = self.pool.get('c.intervention')
        for interv in self.browse(cr, uid, ids, context=context):
            intervention_ids = obj_intervention.search(cr, uid, [('centre_id', '=', intervention_id)], order='date_intv', context=context)
            if intervention_ids:
                res[intervention_id] = intervention_ids[-1:][0]
            else:
                res[intervention_id] = False
        return res

and it gaves me this error: would any one please tells me what could be wrong with it :

TypeError: _get_latest_intervention() takes at least 6 arguments (5 given)