def METHOD_NAME(data):
    metadata = {
        "accession_number": data.get("accession_number"),
        "date": data.get("object_date"),
        "description": data.get("description"),
        "medium": data.get("medium"),
        "credit_line": data.get("credit_line"),
        "classification": data.get("classification"),
    }
    return {k: v for k, v in metadata.items() if v is not None}