code: def test_scoping_option(self, test_class):
      mixed_precision.enable(tf.float32)
  
      x = tf.Variable([[1.0, 9.0], [8.0, 9.0]])
      d = test_class(x)
      d.check_type = mixed_precision.modes([tf.float32, tf.float16])(
          d.check_type
      )
  
      with mixed_precision.scope(tf.float16):
          self.assertEqual(
              d.check_type(x, tf.float32).dtype, tf.float32
          )
          self.assertEqual(
              d.check_type(x, tf.float16).dtype, tf.float32
          )
  
      self.assertEqual(d.check_type(x, tf.float32).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 12 for calling the MixedPrecisionClassTest obj's underlying member method code with example usage: obj.test_scoping_option(test_class) without return types