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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_meta_lang(self):
 """\ Extract content language from meta """

        # we have a lang attribute in html
        attr = self.parser.getAttribute(self.article.doc, attr='lang')
        if attr is None:
            # look up for a Content-Language in meta
            items = [
                {'tag': 'meta', 'attr': 'http-equiv', 'value': 'content-language'},
                {'tag': 'meta', 'attr': 'name', 'value': 'lang'}
            ]
            for item in items:
                meta = self.parser.getElementsByTag(self.article.doc, **item)
                if meta:
                    attr = self.parser.getAttribute(meta[0], attr='content')
                    break

        if attr:
            value = attr[:2]
            if re.search(RE_LANG, value):
                return value.lower()

        return None