code: def load_from_rdf_file(self, rdf_file):
          
          self.graph = rdflib.Graph()
          self.graph.parse(os.path.abspath(rdf_file), format='nt')
          self.initialize()
docs: Initialize given an RDF input file representing the hierarchy."
  
          Parameters
          ----------
          rdf_file : str
              Path to an RDF file.