code: def testCustomNestTraceTypePlaceholderValue(self):
      trace_components1 = (
          default_types.Literal(1.0),
          default_types.Literal(2.0),
      )
      t1 = custom_nest_trace_type.CustomNestTraceType(
          MaskedValuePair, (True,), trace_components1
      )
  
      mvp1 = MaskedValuePair(mask=True, value1=1.0, value2=2.0)
      phv1 = t1.placeholder_value(None)
      self.assertEqual(phv1.mask, mvp1.mask)
      self.assertEqual(phv1.value1, mvp1.value1)
      self.assertEqual(phv1.value2, mvp1.value2)
  
      trace_components2 = (
          default_types.Literal(2),
          default_types.Literal(1),
      )
      t2 = custom_nest_trace_type.CustomNestTraceType(
          MaskedValuePair, (False,), trace_components2
      )
      mvp2 = MaskedValuePair(mask=False, value1=2, value2=1)
      phv2 = t2.placeholder_value(None)
      self.assertEqual(phv2.mask, mvp2.mask)
      self.assertEqual(phv2.value1, mvp2.value1)
      self.assertEqual(phv2.value2, mvp2.value2)
  
imports: import dataclasses
  from typing import Any
  from tensorflow.core.function.trace_type import custom_nest_trace_type
  from tensorflow.core.function.trace_type import default_types
  from tensorflow.python.platform import test
  from tensorflow.python.types import trace
label_desc: Use image node_id 2 for calling the CustomNestTraceTypeTest obj's underlying member method code with example usage: obj.testCustomNestTraceTypePlaceholderValue() without return types