docstr: Test properties for 'mixed_float16'.
docstr_tok: ["Test","properties","for","'mixed_float16","'","."]
code: def test_properties_mixed_float16(self):
      """Test properties for 'mixed_float16'."""
      policy = DTypePolicy("mixed_float16")
      self.assertEqual(policy.compute_dtype, "float16")
      self.assertEqual(policy.variable_dtype, "float32")
  
imports: from keras.mixed_precision import DTypePolicy
  from keras.mixed_precision import dtype_policy
  from keras.mixed_precision import set_dtype_policy
  from keras.testing import test_case
label_desc: Use image node_id 4 for calling the DTypePolicyTest obj's underlying member method code with example usage: obj.test_properties_mixed_float16() without return types