如何将根添加到 XML 文件？

如何解决如何将根添加到 XML 文件？

<event time="0.0" type="actend" person="770885_2_Person" link="271711" actType="other"  />
    <event time="0.0" type="departure" person="770885_2_Person" link="271711" legMode="car"  />
    <event time="0.0" type="PersonEntersvehicle" person="770885_2_Person" vehicle="770885_2_Person"  />
    <event time="0.0" type="vehicle enters traffic" person="770885_2_Person" link="271711" vehicle="770885_2_Person" networkMode="car" relativePosition="1.0"  />
    <event time="1.0" type="left link" link="271711"  />
    <event time="1.0" type="entered link" link="271715" vehicle="770885_2_Person"  />
    <event time="15.0" type="left link" link="271715"  />
    <event time="15.0" type="entered link" link="535413" vehicle="770885_2_Person"  />
    <event time="17.0" type="left link" link="535413"  />
    <event time="17.0" type="entered link" link="813064" vehicle="770885_2_Person"  />
    <event time="19.0" type="left link" link="813064"  />
    <event time="19.0" type="entered link" link="813066" vehicle="770885_2_Person"  />
    <event time="22.0" type="left link" link="813066"  />
    <event time="22.0" type="entered link" link="813068" vehicle="770885_2_Person"  />
    <event time="23.0" type="actend" person="368018_2_Person" link="614790" actType="other"  />
    <event time="23.0" type="departure" person="368018_2_Person" link="614790" legMode="car"  />
    <event time="23.0" type="PersonEntersvehicle" person="368018_2_Person" vehicle="368018_2_Person"  />
    <event time="23.0" type="vehicle enters traffic" person="368018_2_Person" link="614790" vehicle="368018_2_Person" networkMode="car" relativePosition="1.0"  />
    <event time="24.0" type="left link" link="614790"  />
....

缺少根节点，因此，当我执行 treeEvents = et.parse(file_occup_xml) 时，我收到与根缺失相关的错误（当我手动添加根时，上述解析工作正常）。所以我查看了 here 和 here，但是，在这两种情况下，我实际上无法执行 parse() 命令，因为没有 root。

我在这里错过了什么吗？然后如何在该 XML 文件上添加根目录？