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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 retrieve_instance_links(self):
 """Appends on existing instance links Returns: instance_links: A dictionary containing all the instance links in LINKS and not in pipeline_config """

        instance_links = {}
        self.log.debug("LINKS IS %s", LINKS)
        for key, value in LINKS.items():
            if value not in self.pipeline_config['instance_links'].values():
                instance_links[key] = value
        return instance_links