code: def test_pi_width():
      # GH 7075
      rs = np.random.RandomState(1233091)
      y = np.arange(100) + rs.standard_normal(100)
  
      th = ThetaModel(y, period=12, deseasonalize=False)
      res = th.fit()
      pi = res.prediction_intervals(24)
      d = np.squeeze(np.diff(np.asarray(pi), axis=1))
      assert np.all(np.diff(d) > 0)
  
file_path: statsmodels/statsmodels/tsa/forecasting/tests/test_theta.py
imports: from itertools import product
  import numpy
  import pandas
  import pytest
  from statsmodels.tsa.forecasting.theta import ThetaModel
label_desc: Use image node_id 7 for calling a global function with example usage: test_pi_width() without return types