执行（嵌套）迭代需要2个步骤： sec ，然后点击标题。像这样的东西：

Do a (nested) iteration in 2 steps: on sec and then on title. Something like:

for sec in parent.iter("sec"):
    for title in sec.iter("title"):
        text = title.text
        if text and "methods" in text.lower():
            print("**title: " + text + " **** sec id: " + sec.get("id", ""))

有关更多详细信息，请检查 [Python 3.Docs]：xml.etree.ElementTree-ElementTree XML API 。

For more details, check [Python 3.Docs]: xml.etree.ElementTree - The ElementTree XML API.