function bbp_list_forums( $args = array() ) {

	// Parse arguments against default values
	$r = bbp_parse_args( $args, array(
		'before'           => '<ul class="bbp-forums-list">',
		'after'            => '</ul>',
		'link_before'      => '<li class="bbp-forum css-sep">',
		'link_after'       => '</li>',
		'sep'              => '',
		'count_before'     => ' (',
		'count_after'      => ')',
		'count_sep'        => ', ',
		'forum_id'         => bbp_get_forum_id(),
		'show_topic_count' => true,
		'show_reply_count' => true,
		'echo'             => true,

		// Retired, use 'sep' instead
		'separator'        => false
	), 'list_forums' );

	/**
	 * Necessary for backwards compatibility
	 * @see https://bbpress.trac.wordpress.org/ticket/2900
	 */
	if ( ! empty( $r['separator'] ) ) {
		$r['sep'] = $r['separator'];
	}

	// Default values
	$links  = array();
	$output = '';

	// Query for subforums
	$sub_forums = ! empty( $r['forum_id'] )
		? bbp_forum_get_subforums( $r['forum_id'] )
		: array();

	// Loop through forums and create a list
	if ( ! empty( $sub_forums ) ) {
		foreach ( $sub_forums as $sub_forum ) {

			// Get forum details
			$count     = array();
			$permalink = bbp_get_forum_permalink( $sub_forum->ID );
			$title     = bbp_get_forum_title( $sub_forum->ID );

			// Show topic count
			if ( ! empty( $r['show_topic_count'] ) && ! bbp_is_forum_category( $sub_forum->ID ) ) {
				$count['topic'] = bbp_get_forum_topic_count( $sub_forum->ID );
			}

			// Show reply count
			if ( ! empty( $r['show_reply_count'] ) && ! bbp_is_forum_category( $sub_forum->ID ) ) {
				$count['reply'] = bbp_get_forum_reply_count( $sub_forum->ID );
			}

			// Counts to show
			$counts = ! empty( $count )
				? $r['count_before'] . implode( $r['count_sep'], $count ) . $r['count_after']
				: '';

			// Subforum classes
			$subforum_classes      = array( 'bbp-forum-link' );
			$subforum_classes      = apply_filters( 'bbp_list_forums_subforum_classes', $subforum_classes, $sub_forum->ID );

			// This could use bbp_get_forum_class() eventually...
			$subforum_classes_attr = 'class="' . implode( ' ', array_map( 'sanitize_html_class', $subforum_classes ) ) . '"';

			// Build this sub forums link
			$links[] = $r['link_before'] . '<a href="' . esc_url( $permalink ) . '" ' . $subforum_classes_attr . '>' . $title . $counts . '</a>' . $r['link_after'];
		}

		// Maybe wrap output
		$output = ! empty( $links )
			? $r['before'] . implode( $r['sep'], $links ) . $r['after']
			: '';
	}

	// Filter output
	$the_list = apply_filters( 'bbp_list_forums', $output, $r, $args );

	// Echo or return the forums list
	if ( ! empty( $r['echo'] ) ) {
		echo $the_list;
	} else {
		return $the_list;
	}
}