Insert after x node minidom xml python

Question

I'm appending a node to an xml, but i want it to insert before some tags, could that be possible?

newNode = xmldoc.createElement("tag2")
txt = xmldoc.createTextNode("value2")
newNode.appendChild(txt)
n.appendChild(newNode)

This is my XML. When I append the child, it add after UniMed, I want it to insert after Cantidad and before UniMed. (Simplified version of my XML) "Item" can have more childs, and i do not know how many.

<ns0:Item>
      <ns0:Cantidad>1</ns0:Cantidad>
      <ns0:UniMed>L</ns0:UniMed>
</ns0:Item>

I think i can solve it by reading al the childs of Item, erase them, and then add them in the order I want. But i dont think its the best idea...

Any ideas?

---

EDITED

SOLUTION

itemChildNodes = n.childNodes
n.insertBefore(newNode, itemChildNodes[itemChildNodes.length-2])

Answer 1

Use insertBefore method to insert New created tag.

Demo:

>>> from xml.dom import minidom
>>> content = """
... <xml>
...     <Item>
...           <Cantidad>1</Cantidad>
...           <UniMed>L</UniMed>
...     </Item>
... </xml>
... """
>>> root = minidom.parseString(content)
>>> insert_tag = root.createElement("tag2")
>>> htext = root.createTextNode('test')
>>> insert_tag.appendChild(htext)
<DOM Text node "'test'">
>>> 
>>> items = root.getElementsByTagName("Item")
>>> item = items[0]
>>> item_chidren = item.childNodes
>>> item.insertBefore(insert_tag, item_chidren[2])
<DOM Element: tag2 at 0xb700da8c>
>>> root.toxml()
u'<?xml version="1.0" ?><xml>\n\t<Item>\n\t      <Cantidad>1</Cantidad><tag2>test</tag2>\n\t      <UniMed>L</UniMed>\n\t</Item>\n</xml>'
>>>