code: def test_get_filenames_in_tag(mocker: MockerFixture) -> None:
      tag = _get_tags(dataset_id=utils.generate_id())[0]
      mocker.patch.object(
          ApiWorkflowClient, "__init__", return_value=None
      )
      mocked_get_filenames = mocker.patch.object(
          ApiWorkflowClient,
          "get_filenames",
          return_value=[f"file{i}" for i in range(3)],
      )
  
      client = ApiWorkflowClient()
      client._dataset_id = "dataset-id"
      result = client.get_filenames_in_tag(tag_data=tag)
      assert result == ["file0", "file2"]
      mocked_get_filenames.assert_called_once()
  
file_path: lightly/tests/api_workflow/test_api_workflow_tags.py
imports: from typing import List, Optional
  import pytest
  from pytest_mock import MockerFixture
  from lightly.api import ApiWorkflowClient
  from lightly.api.api_workflow_tags import TagDoesNotExistError
  from lightly.openapi_generated.swagger_client.models import TagCreator, TagData
  from tests.api_workflow import utils
label_desc: Use image node_id 6 for calling a global function with example usage: test_get_filenames_in_tag(mocker) without return types