def _to_firestore_operator(
    operator: FilterOperator,
) -> str:
    """Convert from standard operator to Firestore operator."""
    try:
        return {
            FilterOperator.EQ: "==",
            FilterOperator.NE: "!=",
            FilterOperator.GT: ">",
            FilterOperator.GTE: ">=",
            FilterOperator.LT: "<",
            FilterOperator.LTE: "<=",
            FilterOperator.IN: "in",
            FilterOperator.NIN: "not-in",
            FilterOperator.CONTAINS: "array-contains",
        }.pop(operator)
    except KeyError as exc:
        raise ValueError(f"Operator {operator} not supported in Firestore.") from exc
Convert from standard operator to Firestore operator.
llama-index-integrations/vector_stores/llama-index-vector-stores-firestore/llama_index/vector_stores/firestore/base.py