code: def setUp(self):
      stop_trigger = (2, "iteration")
      extension_trigger = (1, "iteration")
      self.filename = "variable_statistics_plot_test.png"
  
      self.trainer = testing.get_trainer_with_mock_updater(
          stop_trigger=stop_trigger
      )
  
      x = numpy.random.rand(1, 2, 3)
      self.extension = extensions.VariableStatisticsPlot(
          chainer.variable.Variable(x),
          trigger=extension_trigger,
          filename=self.filename,
      )
      self.trainer.extend(self.extension, extension_trigger)
  
file_path: chainer/tests/chainer_tests/training_tests/extensions_tests/test_variable_statistics_plot.py
imports: import os
  import unittest
  import numpy
  import six
  import chainer
  from chainer import testing
  from chainer.training import extensions
label_desc: Use image node_id 1 for calling the TestVariableStatisticsPlot obj's underlying member method code with example usage: obj.setUp() without return types