input: 
  def predict_temperature(temperature_list, alpha=0.5):
      """
      Predict the next day's forecasted temperature using the exponential smoothing algorithm.
      This method takes into account the past few days' forecasted temperatures.
      
      >>> predict_temperature([21, 22, 20])
      20.5
      """
      predicted_temperature = temperature_list[-1]  # Initial prediction
      for temperature in reversed(temperature_list[:-1]):
          predicted_temperature = alpha * temperature + (1 - alpha) * predicted_temperature
      return predicted_temperature
  
output:     predicted_temperature = temperature_list[-1]  # Initial prediction
      for temperature in reversed(temperature_list[:-1]):
          predicted_temperature = alpha * temperature + (1 - alpha) * predicted_temperature
      return predicted_temperature