How can one ensure that the XML schema matches when sending XML files via nusoap in PHP?

When sending XML files via nusoap in PHP, one can ensure that the XML schema matches by defining the schema in the WSDL file and validating the XML against this schema before sending it. This can be done using the `validateSchema` method provided by nusoap. By validating the XML against the defined schema, any discrepancies or errors in the XML structure can be identified and corrected before sending it.

// Define the XML schema in the WSDL file
$wsdl = "example.wsdl";

// Load the XML file
$xml = file_get_contents("example.xml");

// Create a nusoap client
$client = new nusoap_client($wsdl, true);

// Validate the XML against the schema
if ($client->validateSchema($xml)) {
    // Send the XML file
    $response = $client->call('exampleMethod', array('xml' => $xml));
    echo $response;
} else {
    echo "XML does not match the schema.";
}