python lxml库生成xml文件-节点命名空间问题

lxml库，处理xml很强大，官方文档：https://lxml.de/tutorial.html#namespaces

例如：

我们要生成如下格式的报文：

<ttt:jesson xmlns:ttt="http://www.hellojesson/ttt" guid="" version="1.0" xsi="http://www.hahaha.com">
  <ttt:order>
    <ttt:orderhead>
      <ttt:guid/>
    </ttt:orderhead>
  </ttt:order>
</ttt:jesson>

就可以参考如下的样例代码实现：

# 导入库
import lxml.etree as etree

# 注册指定命名空间
etree.register_namespace("ttt", "http://www.hellojesson/ttt")
# 生成根节点
root = etree.Element("{http://www.hellojesson/ttt}jesson", xsi="http://www.hahaha.com", guid="", version="1.0")
# 生成子节点：
order = etree.SubElement(root, "{http://www.hellojesson/ttt}order")
orderhead = etree.SubElement(order, "{http://www.hellojesson/ttt}orderhead")
guid = etree.SubElement(orderhead, "{http://www.hellojesson/ttt}guid")

# 节点赋值
order.text = "text"
orderhead.text = ""
guid.text = "hello nihao"

# 输出 查看效果
print(etree.tostring(root, pretty_print=True))