* @param string $type any valid xmlrpc type name (lowercase): i4, int, boolean, string, double, dateTime.iso8601,
* base64, array, struct, null.
* If null, 'string' is assumed.
* @param string $type any valid xmlrpc type name (lowercase): i4, int, boolean, string, double, dateTime.iso8601,
* base64, array, struct, null.
* If null, 'string' is assumed.