import meld3

def page(insertions):
    for insertion in insertions:
        target, targetid, source, sourceid = insertion
        insertreplace(target=target, source=source, targetid=targetid
                      sourceid=sourceid)
    return target

def parse(xml):
    return meld3.parse_html(xml)

def transform(element, context, request):
    return element

def insertreplace(target, source, targetid=None, sourceid=None):
    if targetid is not None:
        target = target.findmeld(targetid)
    if sourceid is not None:
        source = source.findmeld(sourceid)
    for child in target.getchildren():
        child.deparent()
    target.text = None
    target.append(source)
    return target