code: def test2_ppc():
      """
      Tests PPC value
      """
      model = pf.GASX(
          formula="y ~ x1 + x2", data=data, ar=1, sc=1, family=pf.t()
      )
      x = model.fit("BBVI", iterations=100)
      p_value = model.ppc()
      assert 0.0 <= p_value <= 1.0
  
imports: import numpy
  import pandas
  import pyflux
label_desc: Use image node_id 47 for calling a global function with example usage: test2_ppc() without return types