Fetch related entity information.

        Fetches metadata, stats and extra-info for the supplied entities.

        @param ids The entity ids to fetch related information for. A list of
            entity id dicts from the charmstore.

def fetch_related(self, ids):
        """Fetch related entity information.

        Fetches metadata, stats and extra-info for the supplied entities.

        @param ids The entity ids to fetch related information for. A list of
            entity id dicts from the charmstore.
        """
        if not ids:
            return []
        meta = '&id='.join(id['Id'] for id in ids)
        url = ('{url}/meta/any?id={meta}'
               '&include=bundle-metadata&include=stats'
               '&include=supported-series&include=extra-info'
               '&include=bundle-unit-count&include=owner').format(
                   url=self.url, meta=meta)
        data = self._get(url)
        return data.json().values()