code: def test_tbats_long_fh():
      """Test TBATS with long fh, checks for failure condition in bug #4491."""
      LEN_HISTORY = 50
      train = pd.Series(data=np.random.randint(1, 100, LEN_HISTORY))
  
      # train model
      estimator = TBATS(
          use_box_cox=False,
          use_trend=True,
          use_damped_trend=False,
          sp=10,
          use_arma_errors=False,
      )
      estimator.fit(train)
  
      # failure condition is fh being longer than training data
      long_fh = np.array(range(1, LEN_HISTORY + 2))
  
      fcst = estimator.predict_interval(coverage=0.8, fh=long_fh)
      assert len(fcst) == len(long_fh)
  
imports: import numpy
  import pandas
  import pytest
  from sktime.forecasting.tbats import TBATS
  from sktime.tests.test_switch import run_test_for_class
label_desc: Use image node_id 1 for calling a global function with example usage: test_tbats_long_fh() without return types