CI allowed failure - TestReadHtml.test_thousands_macau_index_col[bs4]
```
=================================== FAILURES ===================================
_______________ TestReadHtml.test_thousands_macau_index_col[bs4] _______________
[gw1] linux -- Python 3.6.9 /home/travis/miniconda3/envs/pandas-dev/bin/python
self = <pandas.tests.io.test_html.TestReadHtml object at 0x7f11591bf5c0>
datapath = <function datapath.<locals>.deco at 0x7f1157bd3a60>
    @pytest.mark.slow
    def test_thousands_macau_index_col(self, datapath):
        all_non_nan_table_index = -2
        macau_data = datapath("io", "data", "macau.html")
>       dfs = self.read_html(macau_data, index_col=0, header=0)
pandas/tests/io/test_html.py:389: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
pandas/io/html.py:1095: in read_html
    displayed_only=displayed_only,
pandas/io/html.py:912: in _parse
    raise_with_traceback(retained)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
exc = AttributeError("'NoneType' object has no attribute 'items'",)
traceback = None
    def raise_with_traceback(exc, traceback=Ellipsis):
        """
        Raise exception with existing traceback.
        If traceback is not passed, uses sys.exc_info() to get traceback.
        """
        if traceback == Ellipsis:
            _, _, traceback = sys.exc_info()
>       raise exc.with_traceback(traceback)
E       AttributeError: 'NoneType' object has no attribute 'items'
pandas/compat/__init__.py:46: AttributeError
```

It appears that this started failing with #27962

cc @jbrockmendel 
