code: def testDictTypeSupertype(self):
      dict_type = default_types.Dict
      dict_a = dict_type(
          {
              "a": MockSupertypes2With3(1),
              "b": MockSupertypes2With3(2),
              "c": MockSupertypes2With3(3),
          }
      )
      dict_b = dict_type(
          {
              "a": MockSupertypes2With3(2),
              "b": MockSupertypes2With3(2),
              "c": MockSupertypes2With3(2),
          }
      )
  
      self.assertEqual(
          dict_a, dict_a.most_specific_common_supertype([])
      )
      self.assertIsNone(dict_a.most_specific_common_supertype([dict_b]))
      self.assertEqual(
          dict_b.most_specific_common_supertype([dict_a]),
          dict_type(
              {
                  "a": MockSupertypes2With3(3),
                  "b": MockSupertypes2With3(3),
                  "c": MockSupertypes2With3(3),
              }
          ),
      )
  
imports: import collections
  from tensorflow.core.function.trace_type import default_types
  from tensorflow.core.function.trace_type import serialization
  from tensorflow.python.platform import test
  from tensorflow.python.types import trace
label_desc: Use image node_id 11 for calling the DefaultTypesTest obj's underlying member method code with example usage: obj.testDictTypeSupertype() without return types