code: def test_push_policy(self):
      policy = jmp.get_policy("o=f16")
      test = self
  
      class FooModule(module.Module):
          def __call__(self):
              test.assertEqual(mixed_precision.current_policy(), policy)
  
      mod = FooModule()
      with mixed_precision.push_policy(FooModule, policy):
          self.assertEqual(
              mixed_precision.get_policy(FooModule), policy
          )
          mod()
  
      self.assertIsNone(mixed_precision.get_policy(FooModule))
  
imports: import importlib
  from typing import Optional
  from absl.testing import absltest
  from haiku._src import base
  from haiku._src import conv
  from haiku._src import mixed_precision
  from haiku._src import module
  from haiku._src import test_utils
  from haiku._src import transform
  import jax
  import jax.numpy
  import jmp
label_desc: Use image node_id 9 for calling the MixedPrecisionTest obj's underlying member method code with example usage: obj.test_push_policy() without return types