def get_average_price(plan: str) -> float:
    """
    Get the average price for a plan

    Args:
        plan (str): Plan name. Can be "triple" or "doble"

    Returns:
        float: Average price

    Raises:
        Exception: If the plan is invalid
    """

    if plan == "triple":
        return (10.680 * 0.1667) + (2.223 * 0.2917) + (4.875 * 0.5416)
    if plan == "doble":
        return (10.680 * 0.1667) + (4.280 * 0.8333)

    raise Exception("Invalid plan")