public static function invoicePendingCharges($accountCode, $attributes = array(), $client = null) {
    $uri = Recurly_Client::PATH_ACCOUNTS . '/' . rawurlencode($accountCode) . Recurly_Client::PATH_INVOICES;
    $invoice = new self();
    return Recurly_InvoiceCollection::_post($uri, $invoice->setValues($attributes)->xml(), $client);
  }