docs: 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,
              ),
          )