def action_assign(self, cr, uid, ids, *args):
        """ Changes state of picking to available if all moves are confirmed.
        @return: True
        """
        for pick in self.browse(cr, uid, ids):
            move_ids = [x.id for x in pick.move_lines if x.state == 'confirmed']
            if not move_ids:
                raise osv.except_osv(_('Warning !'),_('Not enough stock, unable to reserve the products.'))
            self.pool.get('stock.move').action_assign(cr, uid, move_ids)
        return True