code: def test_upper_bound_invalid(self):
      with self.assertRaises(ValueError):
          math_ops.upper_bound(tf.zeros((1, 2)), 0, gradient="invalid")
  
file_path: compression/tensorflow_compression/python/ops/math_ops_test.py
imports: from absl.testing import parameterized
  import scipy.stats
  import tensorflow
  from tensorflow_compression.python.ops import math_ops
  from tensorflow_compression.python.ops import round_ops
label_desc: Use image node_id 2 for calling the MathTest obj's underlying member method code with example usage: obj.test_upper_bound_invalid() without return types