function ensurePackage(packageName) {
	var package_parts = packageName.split(".");
	var package_so_far = this;
	for (var i = 0; i < package_parts.length; i += 1) {
		var package_part = package_parts[i];
		if (!package_so_far[package_part]) {
			package_so_far[package_part] = {};
		}
		package_so_far = package_so_far[package_part];
	}
	return package_so_far;
}