code: def testGetVariables(self, dtype):
      spec = tensor_spec.TensorSpec([3], dtype, "obs")
      t_normalizer = tensor_normalizer.StreamingTensorNormalizer(spec)
      self.evaluate(tf.compat.v1.global_variables_initializer())
      variables = t_normalizer.variables
      for var in variables:
          self.assertEqual(var.shape, spec.shape)
          self.assertEqual(var.dtype, spec.dtype)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import functools
  from absl.testing import parameterized
  import numpy
  import tensorflow
  from tf_agents.specs import tensor_spec
  from tf_agents.utils import tensor_normalizer
label_desc: Use image node_id 1 for calling the StreamingTensorNormalizerTest obj's underlying member method code with example usage: obj.testGetVariables(dtype) without return types