i am trying to get pricelist with the help of nusoap_client in php. but i cant do it.

require_once('lib/nusoap.php');

$rap_soapUrl = "https://technet.rapaport.com/webservices/prices/rapaportprices.asmx?wsdl";
$soap_Client = new nusoap_client($rap_soapUrl, 'wsdl');
$rap_credentials['Username'] = "l1fxoup0edjgdr5dhdrk9dwhssbldo";
$rap_credentials['Password'] = "YiT8iqp4";

$result = $soap_Client->call('Login', $rap_credentials);
$rap_auth_ticket = $soap_Client->getHeaders();

if ($soap_Client->fault) {
echo 'Error: ';
print_r($result);
} else {
// check result
$err_msg = $soap_Client->getError();
if ($err_msg) {
// Print error msg
echo 'Error: '.$err_msg;
} else {
// Print result
echo 'Result: ';
print_r($result);
}
}

Please help me. i am new in programing