code: func (j *Json) Get(key string) *Json {
  	m, err := j.Map()
  	if err == nil {
  		if val, ok := m[key]; ok {
  			return &Json{val}
  		}
  	}
  	return &Json{nil}
  }
docs: // Get returns a pointer to a new `Json` object
  // for `key` in its `map` representation
  //
  // useful for chaining operations (to traverse a nested JSON):
  //    js.Get("top_level").Get("dict").Get("value").Int()