class_docstr: Visitor to determine if a node is ready to run.
code: def _validate_operation_label_uniqueness(self, operation_def):
      assert (
          operation_def.label not in self._visited_operation_def_labels
      ), (
          f"An operation with label {operation_def.label} "
          "already exists in the operations graph."
      )
      self._visited_operation_def_labels.add(operation_def.label)
  
imports: import collections
  import dataclasses
  import hashlib
  from typing import Collection, Dict, Mapping, Optional, Tuple
  from typing import OrderedDict
  import tensorflow
  from tensorflow_transform import analyzer_nodes
  from tensorflow_transform import common_types
  from tensorflow_transform import graph_tools
  from tensorflow_transform import impl_helper
  from tensorflow_transform import nodes
  from tensorflow_transform import tf2_utils
  from tensorflow_transform import tf_utils
  from tensorflow_transform.beam import analyzer_cache
  from tensorflow_transform.beam import beam_nodes
  from tensorflow_transform.beam import combiner_packing_util
label_desc: Use image node_id 2 for calling the _ReadyVisitor obj's underlying member method code with example usage: obj._validate_operation_label_uniqueness(operation_def) without return types