Как получить данные из ячеек?

from lxml import etree

html = """
<table id="journal" class="marks">
    <tbody>
        <tr>
            <td class="s2">
                <strong class="u">HTML</strong>
            </td>
            <td class="tac">
                <span class="mark mY analytics-app-popup-mark" data-num="0">1</span>
                <span class="mark mY analytics-app-popup-mark" data-num="0">2</span>
                <span class="mark mG analytics-app-popup-mark" data-num="0">3</span>
            </td>
        </tr>
    </tbody>
</table>"""

tree = etree.fromstring(html)

for block in tree.xpath("//table[@id='journal']/descendant::span[starts-with(@class, 'mark')]"):
    print(block.xpath("text()"))