Field service _prepare_calendar_event

[MarcosGraficon]

Hey guys, im trying to make a diferent use of the event _prepare_calendar_event i want that if the field person_id that is the person assigned to do the work of that fieldservice in the clock menu should appear to him not the calendar team leader, i tried but im not able to do that any clues?

def _prepare_calendar_event(self):
    model_id = self.env.ref("fieldservice.model_fsm_order").id
    vals = {
        "name": self.name,
        "description": self.description,
        "start": self.scheduled_date_start,
        "stop": self.scheduled_date_end,
        "allday": False,
        "res_model_id": model_id,  # link back with "Document" button
        "res_id": self.id,  # link back with "Document" button
        "location": self._serialize_location(),
        "user_id": self.team_id.calendar_user_id.id,
    }
    vals["partner_ids"] = [(4, self.team_id.calendar_user_id.partner_id.id, False)]
    
    I tried this 
    if self.person_id :
        vals = {
            "name": self.name,
            "description": self.description,
            "start": self.scheduled_date_start,
            "stop": self.scheduled_date_end,
            "allday": False,
            "res_model_id": model_id,  # link back with "Document" button
            "res_id": self.id,  # link back with "Document" button
            "location": self._serialize_location(),
            "user_id": self.person_id.partner_id.id, 
        }
        vals["partner_ids"] = [(4, self.person_id.partner_id.id, False)]
        return vals