code: def test_bbvi_elbo():
      """
      Tests that the ELBO increases
      """
      model = pf.GASX(
          formula="y ~ x1 + x2",
          data=data,
          ar=1,
          sc=1,
          family=pf.Poisson(),
      )
      x = model.fit(
          "BBVI", iterations=500, record_elbo=True, map_start=False
      )
      assert x.elbo_records[-1] > x.elbo_records[0]
  
imports: import numpy
  import pandas
  import pyflux
label_desc: Use image node_id 28 for calling a global function with example usage: test_bbvi_elbo() without return types