docs: def execute_flow(self, custom_command="", is_config=False):
          """ Execute flow which run custom command on device
  
          :param custom_command: the command to execute on device
          :param is_config: if True then run command in configuration mode
          :return: command execution output
          """
  
          responses = []
          if isinstance(custom_command, str):
              commands = [custom_command]
          elif isinstance(custom_command, tuple):
              commands = list(custom_command)
          else:
              commands = custom_command
  
          if is_config:
              mode = self._cli_handler.config_mode
              if not mode:
                  raise Exception(self.__class__.__name__,
                                  "CliHandler configuration is missing. Config Mode has to be defined")
          else:
              mode = self._cli_handler.enable_mode
              if not mode:
                  raise Exception(self.__class__.__name__,
                                  "CliHandler configuration is missing. Enable Mode has to be defined")
  
          with self._cli_handler.get_cli_service(mode) as session:
              for cmd in commands:
                  responses.append(session.send_command(command=cmd))
          return '\n'.join(responses)