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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 guess_url(url):
 """Guess if URL is a http or ftp URL. @param url: the URL to check @ptype url: unicode @return: url with http:// or ftp:// prepended if it's detected as a http respective ftp URL. @rtype: unicode """

    if url.lower().startswith("www."):
        # syntactic sugar
        return "http://%s" % url
    elif url.lower().startswith("ftp."):
        # syntactic sugar
        return "ftp://%s" % url
    return url