我正在建立一个网页爬虫的大学项目。现在我在网页上遇到了测试下拉列表。具体来说，以下页面不使用标准的“下拉列表”类。
https://www.mirrorfiction.com/zh-Hant/book/406
我很难实施决策程序来判断网页是否有下拉列表以及下拉列表是否已被删除。
程序员似乎使用了一个名为btnGa的类或类似的东西。我不能谷歌那个。 我不知道浏览器如何知道下拉标签。 html源太大了。所以我只复制了以下一小部分内容。 html源包含一个ul的navlist类。然后这个ul中的li标签包含另一个ul，它实际上是悬停时的下拉列表。 但我真的看不出浏览器会如何知道这是一个下拉列表。因此，我不知道如何编写测试用例来单击此下拉列表中的按钮。
任何人都可以帮助我识别下拉列表并单击下拉列表项吗？
HTML：
<ul class="navList">
<li class="mobileDisable">
<a data-ga-label="小說" data-ga-action="click" data-ga-category="header" onclick="app.navLiClick(this)" class="hasSub btnGa open" href="https://www.mirrorfiction.com/zh-Hant/list/novel">
<span class="text novel">小說</span>
</a>
<ul>
<li>
<a data-ga-label="小說-仙俠" data-ga-action="click" data-ga-category="header" class="btnGa" href="https://www.mirrorfiction.com/zh-Hant/list/novel/classification/11">
<span class="text">仙俠</span>
<span class="num">/ 16</span>
</a>
</li>
<li>
<a data-ga-label="小說-玄幻" data-ga-action="click" data-ga-category="header" class="btnGa" href="https://www.mirrorfiction.com/zh-Hant/list/novel/classification/9">
<span class="text">玄幻</span>
<span class="num">/ 24</span>
</a>
</li>
<li>
<a data-ga-label="小說-奇幻" data-ga-action="click" data-ga-category="header" class="btnGa" href="https://www.mirrorfiction.com/zh-Hant/list/novel/classification/29">
<span class="text">奇幻</span>
<span class="num">/ 56</span>
</a>
</li>
<li>
<a data-ga-label="小說-武俠" data-ga-action="click" data-ga-category="header" class="btnGa" href="https://www.mirrorfiction.com/zh-Hant/list/novel/classification/10">
<span class="text">武俠</span>
<span class="num">/ 11</span>
</a>
</li>
<li>
<a data-ga-label="小說-科幻" data-ga-action="click" data-ga-category="header" class="btnGa" href="https://www.mirrorfiction.com/zh-Hant/list/novel/classification/8">
<span class="text">科幻</span>
<span class="num">/ 17</span>
</a>
</li>
<li>
<a data-ga-label="小說-恐怖" data-ga-action="click" data-ga-category="header" class="btnGa" href="https://www.mirrorfiction.com/zh-Hant/list/novel/classification/30">
<span class="text">恐怖</span>
<span class="num">/ 11</span>
</a>
</li>
<li>
<a data-ga-label="小說-校園" data-ga-action="click" data-ga-category="header" class="btnGa" href="https://www.mirrorfiction.com/zh-Hant/list/novel/classification/7">
<span class="text">校園</span>
<span class="num">/ 16</span>
</a>
</li>
<li>
<a data-ga-label="小說-愛情" data-ga-action="click" data-ga-category="header" class="btnGa" href="https://www.mirrorfiction.com/zh-Hant/list/novel/classification/1">
<span class="text">愛情</span>
<span class="num">/ 78</span>
</a>
</li>
<li>
<a data-ga-label="小說-寫實" data-ga-action="click" data-ga-category="header" class="btnGa" href="https://www.mirrorfiction.com/zh-Hant/list/novel/classification/5">
<span class="text">寫實</span>
<span class="num">/ 48</span>
</a>
</li>
<li>
<a data-ga-label="小說-歷史" data-ga-action="click" data-ga-category="header" class="btnGa" href="https://www.mirrorfiction.com/zh-Hant/list/novel/classification/6">
<span class="text">歷史</span>
<span class="num">/ 13</span>
</a>
</li>
<li>
<a data-ga-label="小說-驚悚" data-ga-action="click" data-ga-category="header" class="btnGa" href="https://www.mirrorfiction.com/zh-Hant/list/novel/classification/31">
<span class="text">驚悚</span>
<span class="num">/ 24</span>
</a>
</li>
<li>
<a data-ga-label="小說-其它" data-ga-action="click" data-ga-category="header" class="btnGa" href="https://www.mirrorfiction.com/zh-Hant/list/novel/classification/12">
<span class="text">其它</span>
<span class="num">/ 40</span>
</a>
</li>
</ul>
</li>
请考虑按照步骤和代码行打开网址并点击菜单：
from selenium import webdriver
driver=webdriver.Chrome("C:\\Utility\\your_directory\\chromedriver.exe")
#maximize the browser window
driver.maximize_window()
#open the url in the browser
driver.get("https://www.mirrorfiction.com/zh-Hant/book/406")
#click on the first menu item 小說
driver.find_element_by_xpath("//nav[@id='nav']/div/ul/li/a/span[@class='text novel']").click()