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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 find_pingback_href(self, content):
 """ Try to find LINK markups to pingback URL. """

        soup = BeautifulSoup(content, 'html.parser')
        for link in soup.find_all('link'):
            dict_attr = dict(link.attrs)
            if 'rel' in dict_attr and 'href' in dict_attr:
                for rel_type in dict_attr['rel']:
                    if rel_type.lower() == PINGBACK:
                        return dict_attr.get('href')