code: def placeholder_value(self, placeholder_context=None):
      raise NotImplementedError
  
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 4 for calling the MockSupertypes2With3 obj's underlying member method code with example usage: obj.placeholder_value(placeholder_context) without return types