python - 我想将一个元素附加到 xml 的前导

Question

sport.xml 是

<sports>
  <sport order="001">
    <name>football</name>
    <orgin>England</orgin>
  </sport>
  <sport order="002">
    <name>baseball</name>
    <orgin>America</orgin>
  </sport>
</sports>

我想附加一个元素

<?xml version="1.0" encoding="UTF-8" ?>

以xml为首

结果，我想做一个像

<?xml version="1.0" encoding="UTF-8" ?>
<sports>
  <sport order="001">
    <name>football</name>
    <orgin>England</orgin>
  </sport>
  <sport order="002">
    <name>baseball</name>
    <orgin>America</orgin>
  </sport>
</sports>

我写了代码，

import xml.etree.ElementTree as ET 

tree = ET.parse('c:\\pg\sport.xml') 
root = tree.getroot()

但我做不到。我应该如何编写代码以将元素附加到 xml 的前导？