How to use the localstripe.resources.InvoiceItem._api_list_all function in localstripe

def _create_invoice(self):
        pending_items = [ii for ii in InvoiceItem._api_list_all(
            None, customer=self.customer, limit=99)._list
            if ii.invoice is None]

        for si in self.items._list:
            pending_items.append(si)

        # Create associated invoice
        invoice = Invoice(
            customer=self.customer,
            subscription=self.id,
            items=pending_items,
            tax_percent=self.tax_percent,
            default_tax_rates=[tr.id
                               for tr in (self.default_tax_rates or [])],
            date=self.current_period_start)
        invoice._finalize()

raise UserError(400, 'Bad request')

        # return 404 if not existant
        customer_obj = Customer._api_retrieve(customer)
        if subscription_items:
            for si in subscription_items:
                Plan._api_retrieve(si['plan'])  # to return 404 if not existant
                # To return 404 if not existant:
                if si['tax_rates'] is not None:
                    [TaxRate._api_retrieve(tr) for tr in si['tax_rates']]
            # To return 404 if not existant:
            if subscription_default_tax_rates is not None:
                [TaxRate._api_retrieve(tr)
                 for tr in subscription_default_tax_rates]

        pending_items = [ii for ii in InvoiceItem._api_list_all(
            None, customer=customer, limit=99)._list
            if ii.invoice is None]
        if (not upcoming and not subscription and
                not subscription_items and not pending_items):
            raise UserError(400, 'Bad request')

        simulation = subscription_items is not None or \
            subscription_prorate is not None or \
            subscription_tax_percent is not None or \
            subscription_default_tax_rates is not None or \
            subscription_trial_end is not None

        current_subscription = None
        li = [s for s in customer_obj.subscriptions._list
              if subscription is None or s.id == subscription]
        if len(li):