code: def test_save_metadata(self) -> None:
      metadata = [("filename.jpg", {"random_metadata": 42})]
      metadata_filepath = tempfile.mktemp(".json", "metadata")
      io.save_custom_metadata(metadata_filepath, metadata)
  
imports: import csv
  import json
  import tempfile
  import unittest
  from pathlib import Path
  import numpy
  from lightly.utils import io
  from tests.api_workflow.mocked_api_workflow_client import MockedApiWorkflowSetup
label_desc: Use image node_id 1 for calling the TestCLICrop obj's underlying member method code with example usage: obj.test_save_metadata() without return types