code: def on_exp_start(self, empty_output_frame, *args, **kwargs):
      # `self.d` and `self.T.d` (pre-CV) set by `BaseExperiment.on_exp_start`
      self.T.final = empty_output_frame
  
imports: from hyperparameter_hunter.data.data_core import BaseDataChunk
  from copy import deepcopy
label_desc: Use image node_id 1 for calling the HoldoutTargetChunk obj's underlying member method code with example usage: obj.on_exp_start(empty_output_frame) without return types