code: def test_plot_series_interval():
      """Test prediction interval plotting functionality in plot_series."""
      from sktime.forecasting.base import ForecastingHorizon
      from sktime.forecasting.naive import NaiveForecaster
  
      model = NaiveForecaster()
      y = load_airline()
      model.fit(y[:-3])
      fh = ForecastingHorizon(y[-3:].index, is_relative=False)
      pred = model.predict(fh)
      interval = model.predict_interval(fh)
      plot_series(y[:-3], y[-3:], pred, pred_interval=interval)
  
imports: import re
  import numpy
  import pandas
  import pytest
  from sktime.datasets import load_airline
  from sktime.tests.test_switch import run_test_for_class
  from sktime.utils.plotting import plot_correlations, plot_lags, plot_series
  from sktime.utils.validation._dependencies import _check_soft_dependencies
  from sktime.utils.validation.series import VALID_DATA_TYPES
label_desc: Use image node_id 10 for calling a global function with example usage: test_plot_series_interval() without return types