code: def test_per_sample_transform(self, *_, **__):
      return self.custom_transform
  
imports: from typing import Callable
  import pytest
  from flash.core.data.io.input_transform import InputTransform
  from flash.core.utilities.imports import _TOPIC_CORE_AVAILABLE
  from flash.core.utilities.stages import RunningStage
label_desc: Use image node_id 4 for calling the CustomInputTransform obj's underlying member method code with example usage: obj.test_per_sample_transform() and returns: self