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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 get_metadata(self, dataset_identifier, content_type="json"):
        '''
        Retrieve the metadata for a particular dataset.
        '''
        resource = _format_old_api_request(dataid=dataset_identifier, content_type=content_type)
        return self._perform_request("get", resource)