code: def save_report(self, file_path):
          
          try:
              report = self.create_report()
          except coverage.CoverageException as e:
              log.error('Failure to gather coverage:', exc_info=e)
          else:
              with open(file_path, 'w') as report_file:
                  report_file.write(report)
docs: Write coveralls report to file.