code: def process(
      self,
      value: t.Union[t.Optional[str], t.Sequence[t.Optional[str]]],
      state: "ParsingState",
  ) -> None:
      if self.nargs > 1:
          assert value is not None
          holes = sum(1 for x in value if x is None)
          if holes == len(value):
              value = None
          elif holes != 0:
              raise BadArgumentUsage(
                  _("Argument {name!r} takes {nargs} values.").format(
                      name=self.dest, nargs=self.nargs
                  )
              )
  
      if (
          self.nargs == -1
          and self.obj.envvar is not None
          and value == ()
      ):
          # Replace empty tuple with None so that a value from the
          # environment may be tried.
          value = None
  
      state.opts[self.dest] = value  # type: ignore
      state.order.append(self.obj)
  
imports: import typing
  from collections import deque
  from gettext import gettext
  from gettext import ngettext
  from .exceptions import BadArgumentUsage
  from .exceptions import BadOptionUsage
  from .exceptions import NoSuchOption
  from .exceptions import UsageError
label_desc: Use image node_id 2 for calling the Argument obj's underlying member method code with example usage: obj.process(value, state) without return types