private function _get_jwt_aud_uri($method)
{
$last_slash_idx = strrpos($method, '/');
if ($last_slash_idx === false) {
throw new \InvalidArgumentException('service name must have a slash');
}
$service_name = substr($method, 0, $last_slash_idx);
if ($this->hostname_override) {
$hostname = $this->hostname_override;
} else {
$hostname = $this->hostname;
}
return 'https://' . $hostname . $service_name;
}