code: def test_skewt_ppc():
      """
      Tests PPC value
      """
      model = pf.GAS(data=data, ar=1, sc=1, family=pf.Skewt())
      x = model.fit("BBVI", iterations=100)
      p_value = model.ppc()
      assert 0.0 <= p_value <= 1.0
  
file_path: pyflux/pyflux/gas/tests/gas_tests_skewt.py
imports: import numpy
  import pyflux
label_desc: Use image node_id 13 for calling a global function with example usage: test_skewt_ppc() without return types