class_docstr: A helper for constructing the namespace open and close strings for a nested set of namespaces.
  
  e.g. for namespace_str torch::lazy,
  
  prologue:
  namespace torch {
  namespace lazy {
  
  epilogue:
  } // namespace lazy
  } // namespace torch
class_docstr_tok: ["A","helper","for","constructing","the","namespace","open","and","close","strings","for","a","nested","set","of","namespaces",".","e.g",".","for","namespace_str","torch",":",":lazy",",","prologue",":","namespace","torch","{","namespace","lazy","{","epilogue",":","}","\/\/","namespace","lazy","}","\/\/","namespace","torch"]
code: def prologue(self) -> str:
      return self.prologue_
  
imports: import contextlib
  import functools
  import hashlib
  import os
  import re
  import sys
  import textwrap
  from argparse import Namespace
  from dataclasses import fields, is_dataclass
  from enum import auto, Enum
  from typing import Any, Callable, Dict, Generic, Iterable, Iterator, List, Literal, NoReturn, Optional, Sequence, Set, Tuple, TypeVar, Union
  from typing_extensions import Self
  from torchgen.code_template import CodeTemplate
label_desc: Use image node_id 3 for calling the NamespaceHelper obj's underlying member method code with example usage: obj.prologue() and returns: self