def _get_extension_resource(api_root):
    """Return the Review Bot extension resource.

    Args:
        api_root (rbtools.api.resource.Resource):
            The server API root.

    Returns:
        rbtools.api.resource.Resource:
        The extension's API resource.
    """
    return api_root.get_extension(extension_name=
        'reviewbotext.extension.ReviewBotExtension')
