elk-owl-parent/elk-owl-implementation/src/main/java/org/semanticweb/elk/owl/managers/ElkObjectEntityRecyclingFactory.java
@SuppressWarnings("unchecked")
	@Override
	protected <C extends ElkObject> C filter(C candidate) {
		if (candidate instanceof ElkEntity)
			return (C) getCanonicalElkEntity((ElkEntity) candidate);
		else
			return candidate;
	}
@SuppressWarnings("unchecked")
	@Override
	protected <C extends ElkObject> C filter(C candidate) {
		if (candidate instanceof ElkEntity)
			return (C) getCanonicalElkEntity((ElkEntity) candidate);
		else
			return candidate;
	}
TODO: simplify the implementation to use just one weak wrapper