docs: def get_children_display(self, id, **kwargs):
          """ Return a list of concepts or collections that should be displayed under this concept or collection.
  
          :param str id: A concept or collection id.
          :returns: A :class:`lst` of concepts and collections.
          """
          broader = 'broader'
          type_values = "((?Type = skos:Concept) || (?Type = skos:Collection))"
  
          query = """SELECT ?Subject ?Id ?Type ?Term (lang(?Term) as ?Lang)
                  {
                  ?Subject rdf:type ?Type;
                  dc:identifier ?Id; skos:inScheme %s:; gvp:%s %s:%s;.
                  OPTIONAL {
                    {?Subject xl:prefLabel [skosxl:literalForm ?Term]}
                            }
                  FILTER(%s)
                  }""" % (self.vocab_id, broader, self.vocab_id, id, type_values)
  
          ret= self._get_answer(query, **kwargs)
          language = self._get_language(**kwargs)
          sort = self._get_sort(**kwargs)
          sort_order = self._get_sort_order(**kwargs)
          return self._sort(ret, sort, language, sort_order == 'desc')