code: def test_float16_mode_ineligible_func(self):
      mixed_precision.enable(tf.float32)
  
      @mixed_precision.modes([tf.float32, tf.bfloat16])
      def fwd_func(x):
          self.assertEqual(x.dtype, tf.float32)
          return x
  
      x = tf.Variable([[1.0, 3], [5.0, 7.0]])
      self.assertEqual(x.dtype, tf.float32)
  
      mixed_precision.enable(tf.float16)
      self.assertEqual(fwd_func(x).dtype, tf.float32)
      self.assertEqual(fwd_func(x).dtype, tf.float32)
  
imports: from absl.testing import parameterized
  from sonnet.src import base
  from sonnet.src import mixed_precision
  from sonnet.src import test_utils
  import tensorflow
  import tree
label_desc: Use image node_id 3 for calling the MixedPrecisionTest obj's underlying member method code with example usage: obj.test_float16_mode_ineligible_func() and returns: x