class_docstr: Helper class to parse boolean flag that optionally accepts truth value.
code: def __init__(self, option_strings, dest, nargs=None, **kwargs):
      if nargs != "?":
          # This should never happen. This class is only used once below with
          # nargs="?".
          raise ValueError(
              "This parser only supports nargs='?' (0 or 1 additional arguments)"
          )
      super(_ParseBooleanFlag, self).__init__(
          option_strings, dest, nargs=nargs, **kwargs
      )
  
imports: import argparse
  import os
  import sys
  import warnings
  from absl import app
  import tensorflow
  from tensorflow.lite.python import lite
  from tensorflow.lite.python.convert import register_custom_opdefs
  from tensorflow.lite.toco import toco_flags_pb2
  from tensorflow.lite.toco.logging import gen_html
  from tensorflow.python import tf2
  from tensorflow.python.framework import dtypes
  from tensorflow.python.platform import gfile
  from tensorflow.python.util import keras_deps
label_desc: Use image node_id 1 to create a new _ParseBooleanFlag object from inherited base classes: argparse with example: obj = _ParseBooleanFlag(option_strings, dest, nargs)