code: def _locate_initial_commit(debug_store: DebugStorage) -> int:
      for i in range(len(debug_store)):
          log = debug_store.get_log(i)
          if log["key"].endswith(STEP_OUTPUTS_METADATA):
              return i
      return -1
  
file_path: ray/python/ray/workflow/tests/test_storage_failure.py
imports: from hashlib import sha1
  import tempfile
  import pytest
  import ray
  from ray import workflow
  from ray.workflow.storage.debug import DebugStorage
  from ray.workflow.workflow_storage import STEP_OUTPUTS_METADATA
  from ray.workflow.common import asyncio_run
  from ray.workflow.storage.filesystem import FilesystemStorageImpl
  from ray.workflow.tests.utils import _alter_storage
label_desc: Use image node_id 7 for calling a global function with example usage: _locate_initial_commit(debug_store) and returns: unknown, i