code: function Set(iter, options) {
    if (!(this instanceof Set)) return new Set(iter, options);
  
    this._o = {};
    this.length = 0;
  
    // parse options
    if (options) {
      this.byValue = options.byValue || false; // for objects to use values instead of keys
    }
  
    // construct set
    if (iter) {
      if ( iter.constructor === Array) {
        this._arr_construct(iter)
      } else if (iter.constructor === Object) {
        this._obj_construct(iter);
      } else {
        throw new errors.InvalidParametersError("Invalid Object");
      }
    }
  }
docs: Set
  
  to be used as a return object of dynamodb getItem
  @constructor