Enables a data link.

        :param str instance: A Yamcs instance name.
        :param str link: The name of the data link.

def enable_data_link(self, instance, link):
        """
        Enables a data link.

        :param str instance: A Yamcs instance name.
        :param str link: The name of the data link.
        """
        req = rest_pb2.EditLinkRequest()
        req.state = 'enabled'
        url = '/links/{}/{}'.format(instance, link)
        self.patch_proto(url, data=req.SerializeToString())