code: def testCapturedDefaultValueStr(self):
      f_type = function_type.FunctionType(
          [
              function_type.Parameter(
                  "a",
                  function_type.Parameter.POSITIONAL_OR_KEYWORD,
                  True,
                  None,
              ),
          ]
      )
  
      self.assertEqual(str(f_type), "(a=<captured_default_value>)")
  
imports: import collections
  import pickle
  import platform
  from absl.testing import parameterized
  from tensorflow.core.function import trace_type
  from tensorflow.core.function.polymorphism import function_type
  from tensorflow.core.function.polymorphism import function_type_pb2
  from tensorflow.core.function.trace_type import serialization
  from tensorflow.python.framework import func_graph
  from tensorflow.python.platform import test
  from tensorflow.python.types import trace
label_desc: Use image node_id 3 for calling the SerializationTest obj's underlying member method code with example usage: obj.testCapturedDefaultValueStr() without return types