tilast/gist:1b59ac4b8ebfeb570d6f

## gistfile1.js
Region.prototype.addChild = function(child) {
  var self = this;
  child.checked.subscribe = function(newValue) {
    self.setState();
  }
}
	Region.prototype.addChild = function(child) {
	var self = this;
	child.checked.subscribe = function(newValue) {
	self.setState();
	}
	}