code: def testWidthHeight(self, width=80, height=80, steps=10, num_steps=1):
      observation = "RGBD"
      env = deepmind_lab.Lab(
          "lt_chasm",
          [observation],
          config={"height": str(height), "width": str(width)},
      )
      env.reset()
  
      for _ in six.moves.range(steps):
          obs = env.observations()
          action = np.zeros((7,), dtype=np.intc)
          reward = env.step(action, num_steps=num_steps)
  
          self.assertEqual(obs[observation].shape, (4, width, height))
          self.assertEqual(reward, 0.0)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  from absl.testing import absltest
  import numpy
  import six
  import deepmind_lab
label_desc: Use image node_id 9 for calling the DeepMindLabTest obj's underlying member method code with example usage: obj.testWidthHeight(width, height, steps, num_steps) without return types