code: def build_option_parser(parser):
      
      parser.add_argument(
          '--os-rdomanager-oscplugin-api-version',
          metavar='<rdomanager-oscplugin-api-version>',
          default=utils.env(
              'OS_RDOMANAGER_OSCPLUGIN_API_VERSION',
              default=DEFAULT_RDOMANAGER_OSCPLUGIN_API_VERSION),
          help='RDO Manager OSC Plugin API version, default=' +
               DEFAULT_RDOMANAGER_OSCPLUGIN_API_VERSION +
               ' (Env: OS_RDOMANAGER_OSCPLUGIN_API_VERSION)')
      return parser
docs: Hook to add global options
  
      Called from openstackclient.shell.OpenStackShell.__init__()
      after the builtin parser has been initialized.  This is
      where a plugin can add global options such as an API version setting.
  
      :param argparse.ArgumentParser parser: The parser object that has been
          initialized by OpenStackShell.