code: def test_add(self):
      self.assertEqual(
          [{"a": 1}, {"a": 2}, {"b": 2}, {"b": 3}],
          (
              test_combinations.combine(a=[1, 2])
              + test_combinations.combine(b=[2, 3])
          ),
      )
  
file_path: probability/tensorflow_probability/python/internal/test_combinations_test.py
imports: from collections import OrderedDict
  from tensorflow_probability.python.internal import test_combinations
  from tensorflow_probability.python.internal import test_util
label_desc: Use image node_id 4 for calling the TestingCombinationsTest obj's underlying member method code with example usage: obj.test_add() without return types