code: def testStringObervations(self):
      observation = "CUSTOM_TEXT"
      env = deepmind_lab.Lab(
          "tests/text_observation_test",
          [observation],
          config={"height": "32", "width": "32"},
      )
      observation_spec = env.observation_spec()
      observation_spec_lookup = {o["name"]: o for o in observation_spec}
      spec = observation_spec_lookup[observation]
      self.assertEqual(spec["name"], observation)
      self.assertEqual(spec["shape"], ())
      self.assertEqual(spec["dtype"], str)
      env.reset()
      self.assertEqual(
          env.observations()[observation], "Example Output"
      )
  
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 10 for calling the DeepMindLabTest obj's underlying member method code with example usage: obj.testStringObervations() without return types