docs: def write_index_labels(self, targets, output_path):
          """Write the mappings between vertex indices and labels(target vs. not) to a file.
  
          :param list targets: List of known targets.
          :param str output_path: Path to the output file.
          """
          label_mappings = self.get_index_labels(targets)
  
          with open(output_path, "w") as file:
              for k, v in label_mappings.items():
                  print(k, v, sep='\t', file=file)