def _consider_importhook(self, args: Sequence[str]) -> None:
        """Install the PEP 302 import hook if using assertion rewriting.

        Needs to parse the --assert=<mode> option from the commandline
        and find all the installed plugins to mark them for rewriting
        by the importhook.
        """
        ns, unknown_args = self._parser.parse_known_and_unknown_args(args)
        mode = getattr(ns, "assertmode", "plain")

        disable_autoload = getattr(ns, "disable_plugin_autoload", False) or bool(
            os.environ.get("PYTEST_DISABLE_PLUGIN_AUTOLOAD")
        )
        if mode == "rewrite":
            import _pytest.assertion

            try:
                hook = _pytest.assertion.install_importhook(self)
            except SystemError:
                mode = "plain"
            else:
                self._mark_plugins_for_rewrite(hook, disable_autoload)
        self._warn_about_missing_assertion(mode)
Install the PEP 302 import hook if using assertion rewriting.

        Needs to parse the --assert=<mode> option from the commandline
        and find all the installed plugins to mark them for rewriting
        by the importhook.
        
src/_pytest/config/__init__.py