scrap -> accountmove 参考

    def action_validate(self):
        self.ensure_one()
        if float_is_zero(self.scrap_qty,
                         precision_rounding=self.product_uom_id.rounding):
            raise UserError(_('You can only enter positive quantities.'))
        if self.product_id.type != 'product':
            return self.do_scrap()
        precision = self.env['decimal.precision'].precision_get('Product Unit of Measure')
        available_qty = sum(self.env['stock.quant']._gather(self.product_id,
                                                            self.location_id,
                                                            self.lot_id,
                                                            self.package_id,
                                                            self.owner_id,
                                                            strict=True).mapped('quantity'))
        scrap_qty = self.product_uom_id._compute_quantity(self.scrap_qty, self.product_id.uom_id)
        if float_compare(available_qty, scrap_qty, precision_digits=precision) >= 0:
            return self.do_scrap()
        else:
            ctx = dict(self.env.context)
            ctx.update({
                'default_product_id': self.product_id.id,
                'default_location_id': self.location_id.id,
                'default_scrap_id': self.id,
                'default_quantity': scrap_qty,
                'default_product_uom_name': self.product_id.uom_name
            })
            return {
                'name': self.product_id.display_name + _(': Insufficient Quantity To Scrap'),
                'view_mode': 'form',
                'res_model': 'stock.warn.insufficient.qty.scrap',
                'view_id': self.env.ref('stock.stock_warn_insufficient_qty_scrap_form_view').id,
                'type': 'ir.actions.act_window',
                'context': ctx,
                'target': 'new'
            }

    def do_scrap(self):
        self._check_company()
        for scrap in self:
            scrap.name = self.env['ir.sequence'].next_by_code('stock.scrap') or _('New')
            move = self.env['stock.move'].create(scrap._prepare_move_values())
            # master: replace context by cancel_backorder
            move.with_context(is_scrap=True)._action_done()
            scrap.write({'move_id': move.id, 'state': 'done'})
            scrap.date_done = fields.Datetime.now()
        return True

    def _prepare_move_values(self):
        self.ensure_one()
        return {
            'name': self.name,
            'origin': self.origin or self.picking_id.name or self.name,
            'company_id': self.company_id.id,
            'product_id': self.product_id.id,
            'product_uom': self.product_uom_id.id,
            'state': 'draft',
            'product_uom_qty': self.scrap_qty,
            'location_id': self.location_id.id,
            'scrapped': True,
            'location_dest_id': self.scrap_location_id.id,
            'move_line_ids': [(0, 0, {'product_id': self.product_id.id,
                                           'product_uom_id': self.product_uom_id.id, 
                                           'qty_done': self.scrap_qty,
                                           'location_id': self.location_id.id,
                                           'location_dest_id': self.scrap_location_id.id,
                                           'package_id': self.package_id.id, 
                                           'owner_id': self.owner_id.id,
                                           'lot_id': self.lot_id.id, })],
#             'restrict_partner_id': self.owner_id.id,
            'picking_id': self.picking_id.id
        }