code: def test_roundtrip_cdf_ppf(distribution):
      pits = np.arange(1, 100.0) / 100.0
      dist, param = distribution
      dist = dist()
      x = dist.ppf(pits, param)
      p = dist.cdf(x, param)
      assert_almost_equal(pits, p)
  
      pits = 0.3
      x = dist.ppf(pits, param)
      p = dist.cdf(x, param)
      assert_almost_equal(pits, p)
  
file_path: arch/arch/tests/univariate/test_distribution.py
imports: import numpy
  from numpy.random import RandomState, default_rng
  from numpy.testing import assert_almost_equal, assert_array_equal, assert_equal
  import pytest
  from scipy.special import gamma, gammaln
  import scipy.stats
  from arch.univariate.distribution import GeneralizedError, Normal, SkewStudent, StudentsT
label_desc: Use image node_id 4 for calling a global function with example usage: test_roundtrip_cdf_ppf(distribution) without return types