code: def get_finder(sources=None, pip_command=None, pip_options=None):
      # type: (List[Dict[S, Union[S, bool]]], Optional[Command], Any) -> PackageFinder
      
  
      if not pip_command:
          pip_command = get_pip_command()
      if not sources:
          sources = [
              {"url": "https://pypi.org/simple", "name": "pypi", "verify_ssl": True}
          ]
      if not pip_options:
          pip_options = get_pip_options(sources=sources, pip_command=pip_command)
      session = pip_command._build_session(pip_options)
      atexit.register(session.close)
      finder = pip_shims.shims.PackageFinder(
          find_links=[],
          index_urls=[s.get("url") for s in sources],
          trusted_hosts=[],
          allow_all_prereleases=pip_options.pre,
          session=session,
      )
      return finder
docs: Get a package finder for looking up candidates to install
  
      :param sources: A list of pipfile-formatted sources, defaults to None
      :param sources: list[dict], optional
      :param pip_command: A pip command instance, defaults to None
      :type pip_command: :class:`~pip._internal.cli.base_command.Command`
      :param pip_options: A pip options, defaults to None
      :type pip_options: :class:`~pip._internal.cli.cmdoptions`
      :return: A package finder
      :rtype: :class:`~pip._internal.index.PackageFinder`