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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 add_link(self, rel, value, href=None):
 """ Add a Link metadata element to the IOC. :param rel: Type of the link. :param value: Value of the link text. :param href: A href value assigned to the link. :return: True """

        links_node = self.metadata.find('links')
        if links_node is None:
            links_node = ioc_et.make_links_node()
            self.metadata.append(links_node)
        link_node = ioc_et.make_link_node(rel, value, href)
        links_node.append(link_node)
        return True