def _lookup_online(word):
    """Look up word on diki.pl.

    Parameters
    ----------
    word : str
        Word too look up.

    Returns
    -------
    str
        website HTML content.
    """
    URL = "https://www.diki.pl/{word}"
    HEADERS = {
        "User-Agent": (
            "Mozilla/5.0 (compatible, MSIE 11, Windows NT 6.3; "
            "Trident/7.0;  rv:11.0) like Gecko"
        )
    }

    logger.debug("Looking up online: %s", word)
    quoted_word = urllib.parse.quote(word)
    req = urllib.request.Request(URL.format(word=quoted_word), headers=HEADERS)
    with urllib.request.urlopen(req) as response:
        html_string = response.read().decode()

    return html.unescape(html_string)
Look up word on diki.pl.

    Parameters
    ----------
    word : str
        Word too look up.

    Returns
    -------
    str
        website HTML content.