code: def test_dtypes_are_correct_with_mixed_precision(self):
      tf.keras.mixed_precision.set_global_policy("mixed_float16")
      try:
          x = tf.random.uniform((4, 3), dtype=tf.float16)
          layer = gdn.GDN()
          y = layer(x)
          for variable in layer.variables:
              self.assertEqual(variable.dtype, tf.float32)
          self.assertEqual(y.dtype, tf.float16)
      finally:
          tf.keras.mixed_precision.set_global_policy(
              tf.keras.backend.floatx()
          )
  
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 16 for calling the GDNTest obj's underlying member method code with example usage: obj.test_dtypes_are_correct_with_mixed_precision() without return types