class_docstr: Combines semantic segmentation confusion matrices.
class_docstr_tok: ["Combines","semantic","segmentation","confusion","matrices","."]
code: def create_accumulator(self) -> Dict[int, Matrix]:
      return {}
  
imports: import abc
  from typing import Any, Dict, Iterable, List, Optional, Union
  import apache_beam
  import numpy
  from tensorflow_model_analysis.contrib.aggregates import binary_confusion_matrices
  from tensorflow_model_analysis.metrics import metric_types
  from tensorflow_model_analysis.metrics import metric_util
  from tensorflow_model_analysis.metrics import preprocessors
  from tensorflow_model_analysis.proto import config_pb2
label_desc: Use image node_id 2 for calling the _SemanticSegmentationConfusionMatrixCombiner obj's underlying member method code with example usage: obj.create_accumulator() and returns: dict