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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 collection_list(self, resource_id, resource_type="collection"):
 """ Fetches a list of slug representing descriptions within the specified parent description. :param resource_id str: The slug of the description to fetch children from. :param resource_type str: no-op; not required or used in this implementation. :return: A list of strings representing the slugs for all children of the requested description. :rtype list: """


        def fetch_children(children):
            results = []

            for child in children:
                results.append(child["slug"])

                if "children" in child:
                    results.extend(fetch_children(child["children"]))

            return results

        response = self._get(
            urljoin(self.base_url, "informationobjects/tree/{}".format(resource_id))
        )
        tree = response.json()
        return fetch_children(tree["children"])