class_docstr: A wrapper around registered implementations of beam nodes.
class_docstr_tok: ["A","wrapper","around","registered","implementations","of","beam","nodes","."]
code: def __init__(self):
      self._ptransform_by_tag = {}
  
imports: import collections
  import dataclasses
  import enum
  import os
  from typing import Any, Dict, Mapping, Optional
  import uuid
  import apache_beam
  from tensorflow_transform import common_types
  from tensorflow_transform import nodes
  from tfx_bsl.telemetry import util
label_desc: Use image node_id 1 to create a new _PtransformWrapper object  with example: obj = _PtransformWrapper()