code: def _process_pathway_pathway(self, limit):
          
          LOG.info("Processing KEGG pathways to other ids")
          if self.test_mode:
              graph = self.testgraph
          else:
              graph = self.graph
          line_counter = 0
  
          model = Model(graph)
          raw = '/'.join((self.rawdir, self.files['pathway_pathway']['file']))
          with open(raw, 'r', encoding="iso-8859-1") as csvfile:
              filereader = csv.reader(csvfile, delimiter='\t', quotechar='\"')
              for row in filereader:
                  line_counter += 1
                  (pathway_id_1, pathway_id_2) = row
  
                  if self.test_mode and pathway_id_1 not in self.test_ids['pathway']:
                      continue
  
                  pathway_id_1 = 'KEGG-' + pathway_id_1
                  # will look like KEGG-path:map04130 or KEGG-path:ko04130
                  pathway_id_2 = 'KEGG-' + pathway_id_2
  
                  if pathway_id_1 != pathway_id_2:
                      model.addEquivalentClass(pathway_id_1, pathway_id_2)
  
                  if not self.test_mode and limit is not None and line_counter > limit:
                      break
          return
docs: There are "map" and "ko" identifiers for pathways.
          This makes equivalence mapping between them, where they exist.
          :param limit:
          :return: