input: Write a function to predict the next day's forecast temperature using the exponential smoothing algorithm given the past three day's forecast temperatures. The function should return the predicted temperature.
  def predict_temperature(temperature_list):
      alpha = 0.5
      predicted_temperature = temperature_list[-1]
      for temperature in temperature_list[:-1]:
          predicted_temperature = alpha*temperature + (1-alpha)*predicted_temperature
      return predicted_temperature
  assert predict_temperature([21, 22, 20])==21.0
  assert predict_temperature([20, 21, 22])==21.5
  assert predict_temperature([23, 21, 19])==20.0
  assert predict_temperature([18, 20, 21])==20.5
output: def predict_temperature(temperature_list):
      alpha = 0.5
      predicted_temperature = temperature_list[-1]
      for temperature in temperature_list[:-1]:
          predicted_temperature = alpha*temperature + (1-alpha)*predicted_temperature
      return predicted_temperature