function d3_class(ctor, properties) {
try { for (var key in properties) { Object.defineProperty(ctor.prototype, key, { value: properties[key], enumerable: false }); } } catch (e) { ctor.prototype = properties; }
}
function d3_class(ctor, properties) {
try { for (var key in properties) { Object.defineProperty(ctor.prototype, key, { value: properties[key], enumerable: false }); } } catch (e) { ctor.prototype = properties; }
}