code: def test_cross_validation_uncertainty_disabled(
      self, ts_short, backend
  ):
      df = ts_short.copy()
      for uncertainty in [0, False]:
          m = Prophet(
              uncertainty_samples=uncertainty, stan_backend=backend
          )
          m.fit(df, algorithm="Newton")
          df_cv = diagnostics.cross_validation(
              m, horizon="4 days", period="4 days", initial="115 days"
          )
          expected_cols = ["ds", "yhat", "y", "cutoff"]
          assert all(
              col in expected_cols for col in df_cv.columns.tolist()
          )
          df_p = diagnostics.performance_metrics(df_cv)
          assert "coverage" not in df_p.columns
  
imports: import datetime
  import itertools
  import numpy
  import pandas
  import pytest
  from prophet import Prophet, diagnostics
label_desc: Use image node_id 9 for calling the TestCrossValidation obj's underlying member method code with example usage: obj.test_cross_validation_uncertainty_disabled(ts_short, backend) without return types