def METHOD_NAME(self):
    converter = EditorHTMLConverter(
        features=["h1", "bold", "link", "something_i_just_made_up"]
    )
    input_html = (
        "<h1>this heading is allowed</h1> <h2>but not this one</h2> "
        "<p><b>bold</b> <i>italic</i></p>"
        '<p><a href="http://torchbox.com">external link</a> <a data-linktype="page" data-id="2" href="/">internal link</a></p>'
    )
    output_html = converter.to_database_format(input_html)
    expected = (
        "<h1>this heading is allowed</h1> but not this one "
        "<p><b>bold</b> italic</p>"
        '<p><a href="http://torchbox.com">external link</a> <a linktype="page" id="2">internal link</a></p>'
    )
    self.assertHtmlEqual(expected, output_html)