def METHOD_NAME(
    json_data: dict, zone_key: str
) -> Tuple[datetime, ProductionMix]:
    """Extracts data timestamp and sums regional data into totals by key."""
    dt = datetime.fromisoformat(json_data["Data"])
    totals = defaultdict(lambda: 0.0)
    region = REGIONS[zone_key]
    breakdown = json_data[region]["geracao"]
    for generation, val in breakdown.items():
        totals[generation] += val
    del totals["total"]
    production = ProductionMix()
    for mode, value in totals.items():
        mode_name = GENERATION_MAPPING.get(mode, "unknown")
        production.add_value(
            mode_name, value, mode_name in CORRECTED_NEGATIVE_PRODUCTION
        )
    return dt, production