WP_Customize_Setting::multidimensional( $root,  $keys, bool $create = false )

	final protected function multidimensional( &$root, $keys, $create = false ) {
		if ( $create && empty( $root ) )
			$root = array();

		if ( ! isset( $root ) || empty( $keys ) )
			return;

		$last = array_pop( $keys );
		$node = &$root;

		foreach ( $keys as $key ) {
			if ( $create && ! isset( $node[ $key ] ) )
				$node[ $key ] = array();

			if ( ! is_array( $node ) || ! isset( $node[ $key ] ) )
				return;

			$node = &$node[ $key ];
		}

		if ( $create ) {
			if ( ! is_array( $node ) ) {
				// account for an array overriding a string or object value
				$node = array();
			}
			if ( ! isset( $node[ $last ] ) ) {
				$node[ $last ] = array();
			}
		}

		if ( ! isset( $node[ $last ] ) )
			return;

		return array(
			'root' => &$root,
			'node' => &$node,
			'key'  => $last,
		);
	}