@Override
  @Nullable
  public <F extends Facet<?>> F getFacetByType(FacetTypeId<F> typeId) {
    final Collection<F> facets = getFacetsByType(typeId);
    return facets.isEmpty() ? null : facets.iterator().next();
  }
@Override
  @Nullable
  public <F extends Facet<?>> F getFacetByType(FacetTypeId<F> typeId)