message: [tf.data] Clean up the forward compatibility.
diff: @@ -30,7 +30,6 @@ from six.moves import queue as Queue # pylint: disable=redefined-builtin
  from tensorflow.core.framework import graph_pb2
  from tensorflow.python import tf2
  -from tensorflow.python.compat import compat
  from tensorflow.python.data.experimental.ops import distribute_options
  from tensorflow.python.data.experimental.ops import optimization_options
  from tensorflow.python.data.experimental.ops import stats_options
  @@ -4453,7 +4452,6 @@ class _OptimizeDataset(UnaryUnchangedStructureDataset):
  if optimization_configs is None:
  optimization_configs = []
  - if compat.forward_compatible(2020, 8, 6):
  self._optimizations_enabled = convert.optional_param_to_tensor(
  argument_name="optimizations_enabled",
  argument_value=optimizations_enabled,
  @@ -4477,21 +4475,7 @@ class _OptimizeDataset(UnaryUnchangedStructureDataset):
  self._optimizations_default,
  optimization_configs=optimization_configs,
  **self._flat_structure)
  - else:
  - if optimizations_enabled is None:
  - optimizations_enabled = []
  - if optimizations_default is None:
  - optimizations_default = []
  -
  - self._optimizations = ops.convert_to_tensor(
  - optimizations_enabled + optimizations_default,
  - dtype=dtypes.string,
  - name="optimizations")
  - variant_tensor = gen_dataset_ops.optimize_dataset(
  - input_dataset._variant_tensor, # pylint: disable=protected-access
  - self._optimizations,
  - optimization_configs=optimization_configs,
  - **self._flat_structure)
  +
  super(_OptimizeDataset, self).__init__(input_dataset, variant_tensor)
  