How do i create an rss feed from this page?

Hi!

Im trying to create an rss feed from a gmail account. I used this snippet to fetch the main on a custom template:

function checkGmail($username, $password)
 {
 $url = "https://mail.google.com/mail/feed/atom"; 

 $curl = curl_init();
 curl_setopt($curl, CURLOPT_URL, $url);
 curl_setopt($curl, CURLOPT_FOLLOWLOCATION, 1);
 curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
 curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
 curl_setopt($curl, CURLOPT_USERPWD, $username . ":" . $password);
 curl_setopt($curl, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
 curl_setopt($curl, CURLOPT_ENCODING, "");
 $mailData = curl_exec($curl);
 curl_close($curl);

 return $mailData;
 }

 header('Content-Type:text/xml; charset=UTF-8');
 $feed = checkGmail("[email protected]", "password");
 echo $feed;

This outputs the feed on a page great. But i need to create custom validated feed for it, how do i output that correctly?

I tried to create a custom rss, se below, and point it to my template, but it doesn’t work. I guess i need to set up the template with correct rss code combined with the gmail snippet?

add_action( 'after_setup_theme', 'my_rss_template' );
/**
* Register custom RSS template.
*/
function my_rss_template() {
add_feed( 'short', 'my_custom_rss_render' );
}

/**
* Custom RSS template callback.
*/
function my_custom_rss_render() {
get_template_part( 'feed', 'short' );
}