class_docstr: An argparse Action that will raise an exception in order to skip the
  rest of the argument parsing when --help is passed.
  
  This prevents argparse from quitting due to missing required arguments
  when any are defined, for example by ``pytest_addoption``.
  This is similar to the way that the builtin argparse --help option is
  implemented by raising SystemExit.
code: def __call__(self, parser, namespace, values, option_string=None):
      setattr(namespace, self.dest, self.const)
  
      # We should only skip the rest of the parsing after preparse is done.
      if getattr(parser._parser, "after_preparse", False):
          raise PrintHelp
  
imports: import os
  import sys
  from argparse import Action
  from typing import List
  from typing import Optional
  from typing import Union
  import pytest
  from _pytest.config import Config
  from _pytest.config import ExitCode
  from _pytest.config import PrintHelp
  from _pytest.config.argparsing import Parser
  from _pytest.terminal import TerminalReporter
label_desc: Use image node_id 2 for calling the HelpAction obj's underlying member method code with example usage: obj.__call__(parser, namespace, values, option_string) without return types