用于在xml中添加标记的Python代码，其中父标记是具有不同属性的多个标记

我正在使用

XML.etree.ElementTree

解析以下XML文件：

<main>
    <stream id="1" name="some">
        <inner id="500">
              <sub-inner>
                 <inside> 500 </inside>
              <sub-inner>
        <inner>
    <stream id="2" name="some">
        <inner id="500">
              <sub-inner>
                 <inside> 500 </inside>
              <sub-inner>
        <inner>
    </stream>
</main>

500
500

如何将

200

元素插入标记中，其中stream id=“2”one

输出：

<main>
    <stream id="1" name="some">
        <inner>500</inner>
    </stream>
    <stream id="2" name="some">
        <inner>500</inner>
    <outer>200</outer></stream>
</main>

<main>
    <stream id="1" name="some">
        <inner>500</inner>
    </stream>
    <stream id="2" name="some">
        <outer>200</outer><inner>500</inner>
    </stream>
</main>

500
200500

...
stream = root.find('.//stream[@id="2"]')
outer = ET.Element('outer')
outer.text = '200'
stream.insert(0, outer)
print(ET.tostring(root))

<main>
    <stream id="1" name="some">
        <inner>500</inner>
    </stream>
    <stream id="2" name="some">
        <outer>200</outer><inner>500</inner>
    </stream>
</main>