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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 parse_metadata(self):
 """Parse the INDEX_JSON file and reorganize it as a dictionary of lists."""


        all_models = defaultdict(list)

        with open(self.metadata_index_json) as f:
            loaded = json.load(f)

        for m in loaded['index']:
            all_models[m['uniprot_ac']].append(m)

        self.all_models = dict(all_models)