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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 get_lang_tags(index_page):
 """ Collect informations about language of the page from HTML and Dublin core tags and langdetect guesses. Args: index_page (str):
 HTML content of the page you wish to analyze. Returns: list: List of :class:`.SourceString` objects. """

    dom = dhtmlparser.parseString(index_page)

    lang_tags = [
        get_html_lang_tags(dom),
        get_dc_lang_tags(dom),
        [detect_language(dom)],
        get_html_tag_lang_params(dom),
    ]

    return list(sorted(set(
        SourceString(normalize(lang), source=lang.source)
        for lang in sum(lang_tags, [])
    )))