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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 html_overall_stat( overall_stat, digit=5, overall_param=None, recommended_list=()):
 """ Return HTML report file overall stat. :param overall_stat: overall stat :type overall_stat : dict :param digit: scale (the number of digits to the right of the decimal point in a number.) :type digit : int :param overall_param : Overall parameters list for print, Example : ["Kappa","Scott PI] :type overall_param : list :param recommended_list: recommended statistics list :type recommended_list : list or tuple :return: html_overall_stat as str """

    result = ""
    result += "<h2>Overall Statistics : </h2>\n"
    result += '<table style="border:1px solid black;border-collapse: collapse;">\n'
    overall_stat_keys = sorted(overall_stat.keys())
    if isinstance(overall_param, list):
        if set(overall_param) <= set(overall_stat_keys):
            overall_stat_keys = sorted(overall_param)
    if len(overall_stat_keys) < 1:
        return ""
    for i in overall_stat_keys:
        background_color = DEFAULT_BACKGROUND_COLOR
        if i in recommended_list:
            background_color = RECOMMEND_BACKGROUND_COLOR
        result += '<tr align="center">\n'
        result += '<td style="border:1px solid black;padding:4px;text-align:left;background-color:{};"><a href="'.format(
            background_color) + DOCUMENT_ADR + PARAMS_LINK[i] + '" style="text-decoration:None;">' + str(i) + '</a></td>\n'
        if i in BENCHMARK_LIST:
            background_color = BENCHMARK_COLOR[overall_stat[i]]
            result += '<td style="border:1px solid black;padding:4px;background-color:{};">'.format(
                background_color)
        else:
            result += '<td style="border:1px solid black;padding:4px;">'
        result += rounder(overall_stat[i], digit) + '</td>\n'
        result += "</tr>\n"
    result += "</table>\n"
    return result