Parse description of the book.

    Args:
        html_chunk (obj): HTMLElement containing slice of the page with details.

    Returns:
        str/None: Description as string or None if not found.

def _parse_description(html_chunk):
    """
    Parse description of the book.

    Args:
        html_chunk (obj): HTMLElement containing slice of the page with details.

    Returns:
        str/None: Description as string or None if not found.
    """
    description_tag = html_chunk.match(
        ["div", {"class": "kniha_detail_text"}],
        "p"
    )

    if not description_tag:
        return None

    description = get_first_content(description_tag)
    description = description.replace("<br />", "\n")
    description = description.replace("<br/>", "\n")

    return dhtmlparser.removeTags(description).strip()