Papi_Page_Type::get_post_type_supports PHP Method

    protected function get_post_type_supports()
    {
        $supports = ['custom-fields'];
        if (method_exists($this, 'remove')) {
            $output = $this->remove();
            $output = is_string($output) ? [$output] : $output;
            $output = is_array($output) ? $output : [];
            $output = array_filter($output, 'is_string');
            $supports = array_merge($supports, $output);
        }
        $parent_class = get_parent_class($this);
        $parent_remove = method_exists($parent_class, 'remove');
        while ($parent_remove) {
            $parent = new $parent_class();
            $output = $parent->remove();
            $output = is_string($output) ? [$output] : $output;
            $output = is_array($output) ? $output : [];
            $output = array_filter($output, 'is_string');
            $supports = array_merge($supports, $output);
            $parent_class = get_parent_class($parent_class);
            $parent_remove = method_exists($parent_class, 'remove');
        }
        return $supports;
    }