input: def predict_next_day_price(prices: List[float]) -> float:
      """ Predicts the stock price for the next day based on a given trajectory of stock prices.
      >>> predict_next_day_price([10, 10.4, 10.5, 10.6, 10.7, 10.9, 11])
      Predicted stock price for the next day is: 11.1
output:     if len(prices) < 2:
          raise ValueError("At least two prices are required to make a prediction.")
      
      last_price = prices[-1]
      second_last_price = prices[-2]
      
      price_change = last_price - second_last_price
      
      predicted_price = last_price + price_change
      
      return predicted_price