code: public List<ImmutableFunctionalTerm> getClassPredicates() {
  		List<ImmutableFunctionalTerm> classes = new ArrayList<>();
  		for (ImmutableFunctionalTerm p : classPredicates)
  			classes.add(p);
  		classPredicates.clear();
  		return classes;
  	}
docs: Get classes
  They can be retrieved only once, after retrieving everything is cleared.
  @return