code: function (other) {
          assertNotNull(other);
  
          var table = this.table;
  
          forOf(other, function (element) {
              table.add(element);
          });
      }
docs: Modifies the current set so that it contains all elements that are present
  in either the current set or the specified collection.
  @param {Iterable} other The collection to compare to the current set.