Resolved: can only throw exceptions in C# functions?

public class ParkingException : ApplicationException
    {
        public override string Message
        {
            get => "Your car has been towed away!";
        }
    }

public double HoursParked 
        { 
            get => _hoursParked;
            set
                if (_hoursParked > 24)
                {
                    throw new ParkingException();
                }
                else
                {
                    _hoursParked = Math.Ceiling(value);
                }
        }

public void DisplayTotalCost()
        {
            if(HoursParked > 24)
            {
                throw new ParkingException();
            }
        }

...
public double HoursParked { 
  get => _hoursParked;
  set {
    // if value is beoynd the expected range 0..24 we can't accept it
    // we can't correct the value: what should we do with -123 or 45678?
    // since we can't process the given value, we throw exception.
    // Please, note the name: we complain for value being out of range 
    if (value < 0 || value > 24)
      throw new ArgumentOutOfRangeException(nameof(value), 
        "You can park from 0 to 24 hours only!");

   // value is valid, so we assign it
    _hoursParked = Math.Ceiling(value);
  }
}
   
public void DisplayTotalCost() {
  // We should not complain for _hoursParked here: 
  // it's assigned with set and have a valid value;
  // thus no exception is expected to be thrown.
  // If the car is towed, just display this fact:
  if (Math.Ceiling(_hoursParked) >= 24) { //TODO: Put the right condition here
    Console.Write("Sorry, your car is towed away");

    return;
  }

  //TODO: Compute and show the cost here
}
...