code: public void intersectionWith(Multiset<O> multiset) throws ParameterException {
  		Validate.notNull(multiset);
  		for (O o : support()) {
  			if (multiset.multiplicity(o) > 0) {
  				setMultiplicity(o, Math.min(multiplicity(o), multiset.multiplicity(o)));
  			} else {
  				remove(o);
  			}
  		}
  	}
docs: Intersects this multiset with the given multiset.<br>
  This operation changes only this multiset, not the given one.
  
  @param multiset The multiset to intersect with.
  @throws ParameterException