code: def a_test2_predict_nonconstant():
      """
      We should not really have predictions that are constant (should be some difference)...
      This captures bugs with the predict function not iterating forward
      """
      model = ARIMAX(
          formula="y ~ x1 + x2",
          data=data,
          ar=1,
          ma=1,
          family=Exponential(),
      )
      x = model.fit("BBVI", iterations=200)
      predictions = model.predict(
          h=10, oos_data=data_oos, intervals=False
      )
      assert not np.all(predictions.values == predictions.values[0])
  
imports: import numpy
  import pandas
  from pyflux.arma import ARIMAX
  from pyflux.families import Exponential
label_desc: Use image node_id 37 for calling a global function with example usage: a_test2_predict_nonconstant() without return types