input: from typing import List
  
  def predict_next_day_stock_price(model, trajectory: List[float]) -> float:
      """ Predict the stock price for the next day using a given neural network model.
      The model takes in a trajectory of stock prices and outputs the predicted price.
      >>> predict_next_day_stock_price(create_model(), [10, 10.4, 10.5, 10.6, 10.7, 10.9, 11])
      11.1
      """
output:     return model.predict([trajectory])[0][0]