def construct_rss_url(root_url, rss_feed_path):
    """
    Construct URL for the RSS feed.

    Args
      root_url: Blog's root URL.
      rss_feed_path: String or Path object describing the path to the RSS feed
                     under the blog's root directory.

    Returns
      The RSS feed URL as a string.

    """

    sep = '' if root_url[-1] == '/' else '/'
    rss_url = root_url + sep + str(rss_feed_path)
    return rss_url