code: def test_quadratic_gdn_has_correct_output(self):
      x = tf.random.uniform((1, 2, 3, 4), -0.5, 0.5, dtype=tf.float32)
      y = gdn.GDN(
          inverse=False,
          rectify=False,
          alpha_parameter=2,
          epsilon_parameter=0.5,
      )(x)
      self.assertEqual(x.shape, y.shape)
      self.assertAllClose(
          y, x / tf.sqrt(1 + 0.1 * (x**2)), rtol=0, atol=1e-6
      )
  
imports: import os
  from absl.testing import parameterized
  import tensorflow
  from tensorflow_compression.python.layers import gdn
  from tensorflow_compression.python.layers import parameters
label_desc: Use image node_id 8 for calling the GDNTest obj's underlying member method code with example usage: obj.test_quadratic_gdn_has_correct_output() without return types