错误的参数使Gandi API调用区域信息

I am trying to make an API call to the Gandi API. I can successfully make a call for domain.list() and receive the proper output. But I cannot ficure out how to append .zone as indicated in the API docs to get the zone data. .i.e. domain.zone.info()

API call doc:

http://doc.rpc.gandi.net/domain/reference.html#domain.zone.info

code:

require_once 'gandikey.php';

$domain = $_POST['domain'];
$domain_api = XML_RPC2_Client::create(
        'https://rpc.gandi.net/xmlrpc/',
        array('prefix' => 'domain.')
);
$op = $domain_api->__call('zone.info', array($apikey, '14382539'));
echo '<pre>';
var_dump($op);
echo '</pre>';

Output:

Fatal error: Uncaught exception 'XML_RPC2_FaultException' with message 'Error on object : OBJECT_UNKNOWN (CAUSE_BADPARAMETER) [invalid method parameter(s)]' in /usr/local/share/pear/XML/RPC2/Exception.php:283 Stack trace: #0 /usr/local/share/pear/XML/RPC2/Backend/Php/Response.php(129): XML_RPC2_FaultException::createFromDecode(Object(SimpleXMLElement)) #1 /usr/local/share/pear/XML/RPC2/Backend/Php/Client.php(122): XML_RPC2_Backend_Php_Response::decode(Object(SimpleXMLElement)) #2 /usr/home/nyctelecomm/www/mkdomain/gandi-mkzone.php(56): XML_RPC2_Backend_Php_Client->__call('zone.info', Array) #3 {main} thrown in /usr/local/share/pear/XML/RPC2/Exception.php on line 283

How do I get the domain zone information from the Gandi API?

You are required to pass an integer as the second argument. In the test environment at https://rpc.ote.gandi.net/xmlrpc/,

$domain_api->call("zone.info", [$apikey, "115553"]);`

fails with the CAUSE_BADPARAMETER exception whereas

$domain_api->call("zone.info", [$apikey, 115553]);

returns:

array (size=8)
  'name' => string 'Default Gandi zone file' (length=23)
  'versions' => 
    array (size=1)
      0 => int 1
  'date_updated' => 
    object(stdClass)[405]
      public 'scalar' => string '20110705T14:12:19' (length=17)
      public 'xmlrpc_type' => string 'datetime' (length=8)
      public 'timestamp' => int 1309875139
  'id' => int 115553
  'owner' => string 'BACKEND1-GANDI' (length=14)
  'version' => int 1
  'domains' => int 1670
  'public' => boolean true