code: def hierarchy_cycles(rdf, fix=False):
      
      top_concepts = sorted(rdf.subject_objects(SKOS.hasTopConcept))
      status = {}
      for cs, root in top_concepts:
          _hierarchy_cycles_visit(
              rdf, root, None, fix, status=status)
  
      # double check that all concepts were actually visited in the search,
      # and visit remaining ones if necessary
      recheck_top_concepts = False
      for conc in sorted(rdf.subjects(RDF.type, SKOS.Concept)):
          if conc not in status:
              recheck_top_concepts = True
              _hierarchy_cycles_visit(
                  rdf, conc, None, fix, status=status)
      return recheck_top_concepts
docs: Check if the graph contains skos:broader cycles and optionally break these.
  
      :param Graph rdf: An rdflib.graph.Graph object.
      :param bool fix: Fix the problem by removing any skos:broader that overlaps
          with skos:broaderTransitive.