Error when restricting zoom levels using MarkerClusterer in Google Maps API v3-Collection of common programming errors

Looks like an error in the MarkerClusterer to me. Inside this function in the for loop, markers is undefined, which means this.getMarkers() is returning undefined, looks to me like it is just wrong:

/**
 * Returns the bounds of the cluster.
 *
 * @return {google.maps.LatLngBounds} the cluster bounds.
 */
Cluster.prototype.getBounds = function() {
  var bounds = new google.maps.LatLngBounds(this.center_, this.center_);
  var markers = this.getMarkers();
  for (var i = 0, marker; marker = markers[i]; i++) {
    bounds.extend(marker.getPosition());
  }
  return bounds;
};

probably should be something like (not tested):

/**
 * Returns the bounds of the cluster.
 *
 * @return {google.maps.LatLngBounds} the cluster bounds.
 */
Cluster.prototype.getBounds = function() {
  var bounds = new google.maps.LatLngBounds(this.center_, this.center_);
  var markers = this.getMarkers();
  if (markers && markers.length) 
  {
    for (var i = 0; i < markers.length; i++) {
      bounds.extend(markers[i].getPosition());
    }
  } 
  return bounds;
};

Works using MarkerClustererPlus