code: def load_result(result_file, options, run_set_id=None, columns=None,
                  columns_relevant_for_diff=set()):
      
      xml = parse_results_file(result_file, run_set_id=run_set_id, ignore_errors=options.ignore_errors)
      if xml is None:
          return None
  
      result = RunSetResult.create_from_xml(
          result_file, xml, columns=columns, all_columns=options.all_columns,
          columns_relevant_for_diff=columns_relevant_for_diff)
      result.collect_data(options.correct_only)
      return result
docs: Completely handle loading a single result file.
      @param result_file the file to parse
      @param options additional options
      @param run_set_id the identifier of the run set
      @param columns the list of columns
      @param columns_relevant_for_diff a set of columns that is relevant for
                                       the diff table
      @return a fully ready RunSetResult instance or None