code: public Set<BlankNodeOrIRI> getPredicateObjects(TriplesMap tm) {
  		Set<BlankNodeOrIRI> predobjs = new HashSet<>();
  		for (PredicateObjectMap pobj : tm.getPredicateObjectMaps()) {
  			for (PredicateMap pm : pobj.getPredicateMaps()) {
  				BlankNodeOrIRI r = pm.getNode();
  				predobjs.add(r);
  			}
  		}
  		return predobjs;
  	}
docs: Get predicates
  @param tm
  @return