code: def assert_saved_html_file(filename="output.html"):
      output = pathlib.Path(filename)
      assert_that(output.exists() and output.is_file())
      try:
          content = output.open("r", encoding="utf-8").read()
          assert_that(content, is_html_document())
      finally:
          output.unlink()
  
imports: import contextlib
  import io
  import pathlib
  import typing
  from unittest.mock import Mock, patch
  import jsonpickle
  import pandas
  import plotly.express
  import plotly.io
  from hamcrest import all_of, any_of, assert_that, calling, equal_to, greater_than, has_entries, has_length, instance_of, is_, matches_regexp, only_contains, raises
  from ipywidgets import VBox, Widget
  from deepchecks.core.check_result import CheckFailure, CheckResult
  from deepchecks.core.errors import DeepchecksValueError
  from deepchecks.tabular.checks import ColumnsInfo, MixedNulls
  from deepchecks.utils.json_utils import from_json
  from tests.common import DummyCheck, create_check_result, create_suite_result, instance_of_ipython_formatter
label_desc: Use image node_id 46 for calling a global function with example usage: assert_saved_html_file(filename) without return types