Jetpack_Subscriptions::should_email_post_to_subscribers PHP Method

    public function should_email_post_to_subscribers($post)
    {
        $should_email = true;
        if (get_post_meta($post->ID, '_jetpack_dont_email_post_to_subs', true)) {
            return false;
        }
        /**
         * Array of categories that will never trigger subscription emails.
         *
         * Will not send subscription emails from any post from within these categories.
         *
         * @module subscriptions
         *
         * @since 3.7.0
         *
         * @param array $args Array of category slugs or ID's.
         */
        $excluded_categories = apply_filters('jetpack_subscriptions_exclude_these_categories', array());
        // Never email posts from these categories
        if (!empty($excluded_categories) && in_category($excluded_categories, $post->ID)) {
            $should_email = false;
        }
        /**
         * ONLY send subscription emails for these categories
         *
         * Will ONLY send subscription emails to these categories.
         *
         * @module subscriptions
         *
         * @since 3.7.0
         *
         * @param array $args Array of category slugs or ID's.
         */
        $only_these_categories = apply_filters('jetpack_subscriptions_exclude_all_categories_except', array());
        // Only emails posts from these categories
        if (!empty($only_these_categories) && !in_category($only_these_categories, $post->ID)) {
            $should_email = false;
        }
        return $should_email;
    }