code: def test_approx_quantile(self):
      batch_size = 6
      df = np.linspace(1.0, 20.0, batch_size).astype(np.float64)[
          ..., np.newaxis
      ]
      nc = np.linspace(0.0, 20.0, batch_size).astype(np.float64)[
          ..., np.newaxis
      ]
      x = np.linspace(0.0, 1.0, 13).astype(np.float64)
      dist = noncentral_chi2.NoncentralChi2(
          df=df, noncentrality=nc, validate_args=True
      )
  
      expected_quantile = stats.ncx2.ppf(x, df, nc)
  
      quantile = dist.quantile_approx(x)
      self.assertEqual(quantile.shape, (batch_size, 13))
      self.assertAllClose(self.evaluate(quantile), expected_quantile)
  
imports: from absl.testing import parameterized
  import numpy
  from scipy import stats
  import tensorflow
  from tensorflow_probability.python.distributions import noncentral_chi2
  from tensorflow_probability.python.distributions.internal import statistical_testing
  from tensorflow_probability.python.internal import test_util
label_desc: Use image node_id 14 for calling the NoncentralChi2Test obj's underlying member method code with example usage: obj.test_approx_quantile() without return types