void (final LinkedHashSet<? super Facet<?>> facets, final Facet<?> facet) { final Facet<?> underlyingFacet = facet.getUnderlyingFacet(); if (underlyingFacet != null && !facets.contains(facet)) { addUnderlyingFacets(facets, underlyingFacet); } facets.add(facet); }