class_docstr: A sentinel singleton class used to distinguish omitted keyword arguments
  from those passed in with the value None (which may have different behavior).
  
  For example:
  
  ```py
  def get(timeout: Union[int, NotGiven, None] = NotGiven()) -> Response:
      ...
  
  
  get(timeout=1)  # 1s timeout
  get(timeout=None)  # No timeout
  get()  # Default timeout behavior, which may not be statically known at the method definition.
  ```
class_docstr_tok: ["A","sentinel","singleton","class","used","to","distinguish","omitted","keyword","arguments","from","those","passed","in","with","the","value","None","(","which","may","have","different","behavior",")",".","For","example",":","``","`","py","def","get","(","timeout",":","Union","[","int",",","NotGiven",",","None","]","=","NotGiven","(",")",")","-",">","Response",":","...","get","(","timeout=1",")","#","1s","timeout","get","(","timeout=None",")","#","No","timeout","get","(",")","#","Default","timeout","behavior",",","which","may","not","be","statically","known","at","the","method","definition",".","``","`"]
code: def __bool__(self) -> Literal[False]:
      return False
  
imports: from __future__ import annotations
  from os import PathLike
  from typing import IO, TYPE_CHECKING, Any, Dict, List, Type, Tuple, Union, Mapping, TypeVar, Callable, Optional, Sequence
  from typing_extensions import Literal, Protocol, TypeAlias, TypedDict, override, runtime_checkable
  import httpx
  import pydantic
  from httpx import URL, Proxy, Timeout, Response, BaseTransport, AsyncBaseTransport
label_desc: Use image node_id 1 for calling the NotGiven obj's underlying member method code with example usage: obj.__bool__() and returns: False