code: def test_poisson_predict_is_length():
      """
      Tests that the prediction IS dataframe length is equal to the number of steps h
      """
      model = pf.GASLLEV(data=countdata, family=pf.Poisson())
      x = model.fit()
      assert model.predict_is(h=5).shape[0] == 5
  
imports: import numpy
  import pyflux
  import pandas
label_desc: Use image node_id 10 for calling a global function with example usage: test_poisson_predict_is_length() without return types