code: def get_default_trial_command_channel() -> TrialCommandChannel:
      """
      Get the default trial command channel.
      Create one if it does not exist.
  
      Returns
      -------
      The default trial command channel.
      """
      if _channel is None:
          return set_default_trial_command_channel()
  
      return _channel
  
label_desc: Use image node_id 2 for calling a global function with example usage: get_default_trial_command_channel() and returns: _channel, set_default_trial_command_channel