code: def _validate_snapshot(path, metadata, element_spec, compression):
      """Validates a tf.data distributed snapshot.
  
      Args:
        path: Root path of the distributed snapshot.
        metadata: The DistributedSnapshotMetadata of the snapshot.
        element_spec: Dataset element_spec.
        compression: Compression method used for saving.
  
      Raises:
        ValueError if the snapshot is invalid.
      """
  
      if not gfile.Exists(path):
          raise ValueError(
              f"Failed to load tf.data snapshot at {path}: The snapshot directory "
              "does not exist."
          )
  
      error_file = _pywrap_snapshot_utils.TF_DATA_SnapshotErrorFilePath(
          path
      )
      if gfile.Exists(error_file):
          with gfile.GFile(error_file, "r") as f:
              raise ValueError(
                  f"Failed to load tf.data snapshot at {path}. The save job failed to "
                  f"write it. Status: {f.read()}"
              )
  
      done_file = _pywrap_snapshot_utils.TF_DATA_SnapshotDoneFilePath(
          path
      )
      if not gfile.Exists(done_file):
          raise ValueError(
              f"Failed to load tf.data snapshot at {path}. The save job has not "
              "finished writing the snapshot."
          )
  
      snapshot_element_spec = _parse_element_spec(metadata.element_spec)
      if element_spec and element_spec != snapshot_element_spec:
          raise ValueError(
              f"Failed to load tf.data snapshot at {path}. User specified "
              f"element_spec {element_spec}, but the actual element_spec is "
              f"{snapshot_element_spec}."
          )
  
      if compression and compression != metadata.compression:
          raise ValueError(
              f"Failed to load tf.data snapshot at {path}. User specified "
              f"compression {compression}, but the actual compression is "
              f"{metadata.compression}."
          )
  
imports: import multiprocessing
  import os
  import time
  from typing import Optional
  from google.protobuf import message
  from google.protobuf import text_format
  from tensorflow.core.protobuf import snapshot_pb2
  from tensorflow.python.data.experimental.service import _pywrap_snapshot_utils
  from tensorflow.python.data.ops import dataset_ops
  from tensorflow.python.data.ops import structured_function
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import errors
  from tensorflow.python.framework import tensor_spec
  from tensorflow.python.ops import gen_experimental_dataset_ops
  from tensorflow.python.platform import gfile
  from tensorflow.python.saved_model import nested_structure_coder
label_desc: Use image node_id 5 for calling a global function with example usage: _validate_snapshot(path, metadata, element_spec, compression) without return types