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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def build_option_parser(parser):
 """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. """

    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