Please see comments: ``` typescript interface ObjectHash { [key: string]: any; } var hash: ObjectHash; hash = { "key": "value" } declare class Model { defaults: ObjectHash; } class MyModel1 extends Model { // Okay defaults = hash; } class MyModel2 extends Model { // Why ERROR?! defaults = { "key": "value" }; } class MyModel3 extends Model { // Okay defaults: ObjectHash = { "key": "value" }; } ```