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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 tidy_html(html_buffer, cleaning_lib='utidylib'):
 """ Tidy up the input HTML using one of the installed cleaning libraries. @param html_buffer: the input HTML to clean up @type html_buffer: string @param cleaning_lib: chose the preferred library to clean the HTML. One of: - utidylib - beautifulsoup @return: a cleaned version of the input HTML @note: requires uTidylib or BeautifulSoup to be installed. If the chosen library is missing, the input X{html_buffer} is returned I{as is}. """


    if CFG_TIDY_INSTALLED and cleaning_lib == 'utidylib':
        options = dict(output_xhtml=1,
                       show_body_only=1,
                       merge_divs=0,
                       wrap=0)
        try:
            output = str(tidy.parseString(html_buffer, **options))
        except:
            output = html_buffer
    elif CFG_BEAUTIFULSOUP_INSTALLED and cleaning_lib == 'beautifulsoup':
        try:
            output = str(BeautifulSoup(html_buffer).prettify())
        except:
            output = html_buffer
    else:
        output = html_buffer

    return output