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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 online_help(param=None):
 """ Open online document in web browser. :param param: input parameter :type param : int or str :return: None """

    try:
        PARAMS_LINK_KEYS = sorted(PARAMS_LINK.keys())
        if param in PARAMS_LINK_KEYS:
            webbrowser.open_new_tab(DOCUMENT_ADR + PARAMS_LINK[param])
        elif param in range(1, len(PARAMS_LINK_KEYS) + 1):
            webbrowser.open_new_tab(
                DOCUMENT_ADR + PARAMS_LINK[PARAMS_LINK_KEYS[param - 1]])
        else:
            print("Please choose one parameter : \n")
            print('Example : online_help("J") or online_help(2)\n')
            for index, item in enumerate(PARAMS_LINK_KEYS):
                print(str(index + 1) + "-" + item)
    except Exception:
        print("Error in online help")