def METHOD_NAME():
    headers = normalize_and_validate(
        [
            ("Connection", "close"),
            ("whatever", "something"),
            ("connectiON", "fOo,, , BAR"),
        ]
    )
    assert get_comma_header(headers, b"connection") == [b"close", b"foo", b"bar"]
    headers = set_comma_header(headers, b"newthing", ["a", "b"])
    with pytest.raises(LocalProtocolError):
        set_comma_header(headers, b"newthing", ["  a", "b"])
    assert headers == [
        (b"connection", b"close"),
        (b"whatever", b"something"),
        (b"connection", b"fOo,, , BAR"),
        (b"newthing", b"a"),
        (b"newthing", b"b"),
    ]
    headers = set_comma_header(headers, b"whatever", ["different thing"])
    assert headers == [
        (b"connection", b"close"),
        (b"connection", b"fOo,, , BAR"),
        (b"newthing", b"a"),
        (b"newthing", b"b"),
        (b"whatever", b"different thing"),
    ]