Get the title of the object

        :param lang: Lang to retrieve
        :return: Title string representation
        :rtype: Literal

def get_title(self, lang: str=None) -> Literal:
        """ Get the title of the object

        :param lang: Lang to retrieve
        :return: Title string representation
        :rtype: Literal
        """
        return self.metadata.get_single(key=DC.title, lang=lang) or \
            self.metadata.get_single(key=DCT.title, lang=lang)