code: def test2_predict_is_nonconstant():
      """
      We should not really have predictions that are constant (should be some difference)...
      This captures bugs with the predict function not iterating forward
      """
      predictions = model_b_2.predict_is(h=10, intervals=False)
      assert not np.all(predictions.values == predictions.values[0])
  
imports: import numpy
  import pandas
  import pyflux
label_desc: Use image node_id 39 for calling a global function with example usage: test2_predict_is_nonconstant() without return types