RdfNamespacesHelper.instance_methods.each do |meth|
  namespaces = send(meth)
  document.namespaces(namespaces) if namespaces.is_a?(Hash)
end

document << Iqvoc::Concept.root_class.instance.build_rdf_subject do |scheme|
  @top_concepts.each do |top_concept|
    scheme.Skos::hasTopConcept IqRdf.build_uri(top_concept.origin)
    render_concept(document, top_concept, true)
  end
end