addCollection
addCollection(set: Set);
The addCollection method of the SetMergeIterator class adds the set specified by the value of the set parameter to the merged iterator view.
The parameter value must be a Set type. The Set instance being added does not need to have the same membership type as existing sets associated with the iterator.
An exception is raised if you attempt to add a set that is already attached to the iterator and therefore part of the merged iterator view.