class User extends YupEntity(
 object({
 name: string().required(),
 lastName: string().required(),
 age: number().required().positive().integer(),
 email: string().email(),
 website: string().url().nullable(),
 createdOn: date().default(() => new Date()),
 })) {
 pk() {return this.id}
 get fullName() {
 return `${this.name} ${this.lastName}`;
 }
}