class_docstr: Read-through / write-through cache for MLMD executions.
code: def __init__(self):
      self._cache: MutableMapping[
          int, metadata_store_pb2.Execution
      ] = cachetools.LRUCache(maxsize=1024)
      self._lock = threading.Lock()
  
imports: import collections
  import contextlib
  import copy
  import threading
  import typing
  from typing import Callable, Iterator, MutableMapping, Optional
  import cachetools
  from tfx.orchestration import metadata
  from google.protobuf.internal import containers
  from ml_metadata.proto import metadata_store_pb2
label_desc: Use image node_id 1 to create a new _ExecutionCache object  with example: obj = _ExecutionCache()