code: def test_process(self):
      callback = imaging.ImagingCallback()
      callback.on_batch = MagicMock()
      handler = MagicMock()
      callback = callback.with_handler(handler)
      callback.transform = MagicMock()
      state = "state"
      callback.process(state)
      self.assertTrue(callback.transform.call_count == 1)
      handler.assert_called_once_with(
          callback.transform()[None], 0, "state"
      )
      self.assertTrue(callback.transform().dim.call_count == 1)
  
imports: from unittest import TestCase
  from mock import MagicMock, patch, ANY
  import torch
  import torchbearer
  import torchbearer.callbacks.imaging
  import matplotlib.pyplot
label_desc: Use image node_id 4 for calling the TestImagingCallback obj's underlying member method code with example usage: obj.test_process() without return types