code: def testTrainableVariablesAreCreatedByCall(self, model_type):
      model = self._define_model(
          model_type, self.data_dim, self.num_hidden
      )
      model(self.random_input)
      layer = self._get_maybe_norm_layer(model)
      self.assertLen(layer.trainable_variables, 3)
  
imports: import tempfile
  from absl.testing import parameterized
  import numpy
  import tensorflow.compat.v2
  from tensorflow_probability.python.internal import test_util
  from tensorflow_probability.python.internal import tf_keras
  from tensorflow_probability.python.layers import weight_norm
label_desc: Use image node_id 6 for calling the WeightNormTest obj's underlying member method code with example usage: obj.testTrainableVariablesAreCreatedByCall(model_type) without return types