Tasks:

• see examples
• implement extend(obj, ...objects) so keys from objects will be mixed into obj only if it doesn't contain those keys
• implement wrap(obj, ...funcs) so if obj contains func.name it should be wrapped
• implement mixin logable()
• implement universal equilateral mixin for for N sides (see 6-class.js)
• implement emitable with Object.defineProperty (see 6-evants.js)
• implement mixin for prototypes (not instances)
• implement extend for mixins with additional override:Boolean flag

const mix2 = [
  {
    override: true,
    toString() {
      return `${this.name} - ${this.city} - ${this.born}`;
    }
  },
  {
    override: false,
    age() {
      const year = new Date().getFullYear();
      const born = new Date(this.born).getFullYear();
      return year - born;
    }
  }
];

extend(obj1, mix1, mix2);