I have used the following code but it's providing me the CPT list on front-end files like page-template. but it doesn't provide me the CPT list inside a plugin file, what can I do to get the CPT list inside a plugin file?

$args=array(
    'public'                => true,
    'exclude_from_search'   => false,
    '_builtin'              => false
);  
$post_types = get_post_types($args);