code: def add_backup_operation(self, backup, mode=None):
          
          try:
              if self.options.backup:
                  self.options.backup.ignore_if_operation().execute()
          except OperationError:
              self.backup = backup
docs: Add a backup operation to the version.
  
          :param backup: To either add or skip the backup
          :type backup: Boolean
          :param mode: Name of the mode in which the operation is executed
                       For now, backups are mode-independent
          :type mode: String