def init_argparser(self, argparser):
        """
        Other runtimes (or users of ArgumentParser) can pass their
        subparser into here to collect the arguments here for a
        subcommand.
        """

        super(PackageManagerRuntime, self).init_argparser(argparser)

        # Ideally, we could use more subparsers for each action (i.e.
        # init and install).  However, this is complicated by the fact
        # that setuptools has its own calling conventions through the
        # setup.py file, and to present a consistent cli to end-users
        # from both calmjs entry point and setuptools using effectively
        # the same codebase will require a bit of creative handling.

        # provide this for the setuptools command class.
        actions = argparser.add_argument_group('action arguments')
        count = 0

        for full, short, desc in self.pkg_manager_options:
            args = [
                dash + key
                for dash, key in zip(('-', '--'), (short, full))
                if key
            ]
            # default is singular, but for the argparsed version in our
            # runtime permits multiple packages.
            desc = desc.replace('Python package', 'Python package(s)')
            if not short:
                f = getattr(self.cli_driver, '%s_%s' % (
                    self.cli_driver.binary, full), None)
                if callable(f):
                    count += 1
                    actions.add_argument(
                        *args, help=desc, action=PackageManagerAction,
                        dest=self.action_key, const=(count, f)
                    )
                    if self.default_action is None:
                        self.default_action = f
                    continue  # pragma: no cover
            argparser.add_argument(*args, help=desc, action='store_true')

        argparser.add_argument(
            'package_names', metavar=metavar('package'), nargs='+',
            help="python packages to be used for the generation of '%s'" % (
                self.cli_driver.pkgdef_filename,
            ),
        )