@api.multi
def _compute_is_expired(self):
    for record in self:
        if record.deadline:
            current_date = fields.Date.context_today(record.with_context(tz=record.event_id.date_tz))
            record.is_expired = (record.deadline < current_date)
        else:
            record.is_expired = False
@api.multi
def _compute_is_expired(self):
    for record in self:
        if record.deadline:
            current_date = fields.Date.context_today(record.with_context(tz=record.event_id.date_tz))
            record.is_expired = (record.deadline < current_date)
        else:
            record.is_expired = False