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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 auto_version_url(file_path):
 """ Appends modification time of the file to the request URL in order for the browser to refresh the cache when file changes @param file_path: path to the file, e.g js/foo.js @return: file_path with modification time appended to URL """

    file_md5 = ""
    try:
        file_md5 = md5(open(cfg.get('CFG_WEBDIR') +
                            os.sep + file_path).read()).hexdigest()
    except IOError:
        pass
    return file_path + "?%s" % file_md5