bbPress limit content visibility for non-logged in user

functions.php

// Display Topic Leads
add_filter('bbp_show_lead_topic', 'custom_bbp_show_lead_topic' );
function custom_bbp_show_lead_topic( $show_lead ) {
    if ( !is_user_logged_in() ){
	$show_lead[] = 'true';
	return $show_lead;
}}

// Show Topic Leads to Public or Anonymous visitors
add_filter('bbp_has_replies', 'synth_logged_in_topics');
function synth_logged_in_topics($have_posts){
    if ( !is_user_logged_in() ){
        $have_posts = null;
	echo '<h4 class="login-first alert">This is a private forum.</h4>';
    }
    return $have_posts;
}