code: def _serialize_signature_def_map(
      signature_def_map: _SignatureDefMap,
  ) -> dict[str, bytes]:
      """Serializes SignatureDef values in `signature_def_map`.
  
      Args:
        signature_def_map: Signature key -> SignatureDef mapping.
  
      Returns:
        Signature def map where the values (`SignatureDef`) are serialized.
      """
      signature_def_map_serialized = {}
      for key, signature_def in signature_def_map.items():
          signature_def_map_serialized[
              key
          ] = signature_def.SerializeToString()
  
      return signature_def_map_serialized
  
file_path: tensorflow/tensorflow/compiler/mlir/quantization/stablehlo/python/quantization.py
imports: from typing import Mapping
  from tensorflow.compiler.mlir.quantization.stablehlo import quantization_config_pb2
  from tensorflow.compiler.mlir.quantization.stablehlo.python import pywrap_quantization
  from tensorflow.compiler.mlir.quantization.tensorflow import quantization_options_pb2
  from tensorflow.compiler.mlir.quantization.tensorflow.python import py_function_lib
  from tensorflow.compiler.mlir.quantization.tensorflow.python import save_model
  from tensorflow.core.protobuf import meta_graph_pb2
  from tensorflow.python.saved_model import loader_impl
label_desc: Use image node_id 1 for calling a global function with example usage: _serialize_signature_def_map(signature_def_map) and returns: signature_def_map_serialized