code: def testTupleSupertype(self):
      tuple_a = default_types.Tuple(
          MockSupertypes2With3(1),
          MockSupertypes2With3(2),
          MockSupertypes2With3(3),
      )
      tuple_b = default_types.Tuple(
          MockSupertypes2With3(2),
          MockSupertypes2With3(2),
          MockSupertypes2With3(2),
      )
  
      self.assertEqual(
          tuple_a, tuple_a.most_specific_common_supertype([])
      )
      self.assertIsNone(
          tuple_a.most_specific_common_supertype([tuple_b])
      )
      self.assertEqual(
          tuple_b.most_specific_common_supertype([tuple_a]),
          default_types.Tuple(
              MockSupertypes2With3(3),
              MockSupertypes2With3(3),
              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 6 for calling the DefaultTypesTest obj's underlying member method code with example usage: obj.testTupleSupertype() without return types