code: def test_html_tables() -> None:
      df = pl.DataFrame(
          {"a": [1, 2, 3], "b": [4, 5, 6], "c": [7, 8, 9]}
      )
  
      # default: header contains names/dtypes
      header = "<thead><tr><th>a</th><th>b</th><th>c</th></tr><tr><td>i64</td><td>i64</td><td>i64</td></tr></thead>"
      assert header in df._repr_html_()
  
      # validate that relevant config options are respected
      with pl.Config(tbl_hide_column_names=True):
          header = "<thead><tr><td>i64</td><td>i64</td><td>i64</td></tr></thead>"
          assert header in df._repr_html_()
  
      with pl.Config(tbl_hide_column_data_types=True):
          header = (
              "<thead><tr><th>a</th><th>b</th><th>c</th></tr></thead>"
          )
          assert header in df._repr_html_()
  
      with pl.Config(
          tbl_hide_column_data_types=True,
          tbl_hide_column_names=True,
      ):
          header = "<thead></thead>"
          assert header in df._repr_html_()
  
imports: from __future__ import annotations
  import os
  from pathlib import Path
  from typing import Any, Iterator
  import pytest
  import polars
  import polars.polars
  from polars.config import _POLARS_CFG_ENV_VARS
label_desc: Use image node_id 4 for calling a global function with example usage: test_html_tables() without return types