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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 extract(self, item, list_article_candidate):
 """Compares the extracted titles. :param item: The corresponding NewscrawlerItem :param list_article_candidate: A list, the list of ArticleCandidate-Objects which have been extracted :return: A string, the most likely title """

        list_title = []

        # Save every title from the candidates in list_title.
        for article_candidate in list_article_candidate:
            if article_candidate.title is not None:
                list_title.append(article_candidate.title)

        if not list_title:
            return None

        # Creates a list with matched titles
        list_title_matches = self.find_matches(list_title)
        # Extract title with the most matches
        matched_title = self.extract_match(list_title_matches)

        # Returns the matched title if there is one, else returns the shortest title
        if matched_title:
            return matched_title
        else:
            if list_title_matches:
                return self.choose_shortest_title(set(list_title_matches))
            else:
                return self.choose_shortest_title(list_title)