Is it possible to adjust the object render order (z-order stacking) withing a script?

I found one function but it doesn't look like it's used in the code it's featured in. 
 

def zSort(inNode,idList):
    sortedList=[]
    theid = inNode.get("id")
    if theid in idList:
        sortedList.append(theid)
    for child in inNode:
        if len(sortedList)==len(idList):
            break
        sortedList+=zSort(child,idList)
    return sortedList

https://github.com/Orion7/Inkscape/blob/b6130d280cd98cfa85a1570381609907f204a5cd/extensions/pathmodifier.py

There is an extension included in Inkscape which does this:

Extensions>Arrange>Restack

There is an extension included in Inkscape which does this:

Extensions>Arrange>Restack