class_docstr: Tests function update_target_variables.
class_docstr_tok: ["Tests","function","update_target_variables","."]
docstr: Tests error when tau has wrong type.
docstr_tok: ["Tests","error","when","tau","has","wrong","type","."]
code: def testInvalidTypeTau(self):
      """Tests error when tau has wrong type."""
      target_variables = [tf.Variable(tf.random_normal(shape=[1, 2]))]
      source_variables = [tf.Variable(tf.random_normal(shape=[1, 2]))]
      self.assertRaises(
          TypeError,
          target_update_ops.update_target_variables,
          target_variables,
          source_variables,
          1,
      )
  
file_path: trfl/trfl/target_update_ops_test.py
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from absl.testing import parameterized
  import tensorflow.compat.v1
  from trfl import target_update_ops
label_desc: Use image node_id 5 for calling the UpdateTargetVariablesTest obj's underlying member method code with example usage: obj.testInvalidTypeTau() without return types