code: def test_poisson_no_terms():
      """
      Tests the length of the latent variable vector for an GASX model
      with no AR or SC terms, and tests that the values are not nan
      """
      model = pf.GASX(
          formula="y ~ x1", data=data, ar=0, sc=0, family=pf.Poisson()
      )
      x = model.fit()
      assert len(model.latent_variables.z_list) == 2
      lvs = np.array([i.value for i in model.latent_variables.z_list])
      assert len(lvs[np.isnan(lvs)]) == 0
  
imports: import numpy
  import pandas
  import pyflux
label_desc: Use image node_id 1 for calling a global function with example usage: test_poisson_no_terms() without return types