text: #!/usr/bin/env python3
  # Copyright (c) Facebook, Inc. and its affiliates.
  #
  # This source code is licensed under the MIT license found in the
  # LICENSE file in the root directory of this source tree.
  
  from typing import Dict, Optional, Type
  
  from ax.core.runner import Runner
  from ax.runners.synthetic import SyntheticRunner
  from ax.storage.json_store.encoders import runner_to_dict
  from ax.storage.json_store.registry import DECODER_REGISTRY, ENCODER_REGISTRY
  
  
  """
  Mapping of Runner classes to ints.
  
  All runners will be stored in the same table in the database. When
  saving, we look up the runner subclass in RUNNER_REGISTRY, and store
  the corresponding type field in the database. When loading, we look
  up the type field in REVERSE_RUNNER_REGISTRY, and initialize the
  corresponding runner subclass.
  """
  RUNNER_REGISTRY: Dict[Type[Runner], int] = {SyntheticRunner: 0}
  
  REVERSE_RUNNER_REGISTRY: Dict[int, Type[Runner]] = {
      v: k for k, v in RUNNER_REGISTRY.items()
  }
  
  
  def register_runner(runner_cls: Type[Runner], val: Optional[int] = None) -> None:
      """Add a custom runner class to the SQA and JSON registries.
      For the SQA registry, if no int is specified, use a hash of the class name.
      """
      registered_val = val or abs(hash(runner_cls.__name__)) % (10 ** 5)
      RUNNER_REGISTRY[runner_cls] = registered_val
      REVERSE_RUNNER_REGISTRY[registered_val] = runner_cls
  
      ENCODER_REGISTRY[runner_cls] = runner_to_dict
      DECODER_REGISTRY[runner_cls.__name__] = runner_cls
  