Fatal error: Call to undefined method PayPalPayment::set_account_email() in /home/content/s/j/b/sjbmaine/html/demo/tutorial/_config.php on line 27

<?php

global $project;
$project = 'tutorial';

global $databaseConfig;
$databaseConfig = array(
   "type" => "MySQLDatabase",
   "server" => "servername",
   "username" => "username",
   "password" => "password",
   "database" => "database",
);
SSViewer::set_theme("pixelgreen");
Email::setAdminEmail('test@test.com');
// Sites running on the following servers will be
// run in development mode. See
// http://doc.silverstripe.com/doku.php?id=devmode
// for a description of what dev mode does.
Director::set_dev_servers(array(
   '',
));

// Check if the site is in 'live' mode, use the live credentials.
// otherwise, use test credentials instead to be careful.
if(Director::isLive()) {
   PayPalPayment::set_account_email('mymail@mydomain.com');
} else {
   PayPalPayment::set_test_mode('mymailtest@mydomaintest.com');
}   

?>