import cElementTree as ET

##
# Removes start and stop tags for any element for which the filter
# function returns false.  If you want to remove the entire element,
# including all subelements, use the <b>clear</b> method inside the
# filter callable.
# <p>
# Note that this function modifies the tree in place.
#
# @param elem An element tree.
# @param filter An filter function.  This should be a callable that
#    takes an element as its single argument.

def cleanup(elem, filter):
    out = []
    for e in elem:
        cleanup(e, filter)
        if not filter(e):
            if e.text:
                if out:
                    out[-1].tail += e.text
                else:
                    elem.text += e.text
            out.extend(e)
            if e.tail:
                if out:
                    out[-1].tail += e.tail
                else:
                    elem.text += e.tail
        else:
            out.append(e)
    elem[:] = out

# --------------------------------------------------------------------
# demo code

import copy

DOC2 = """\
<root xmlns='namespace'>
   <element key='value'>text</element>
   <element>text</element>tail
   <empty-element/>
</root>
"""

tree = ET.XML(DOC2)

# remove just the 'element' tags

cleanup(tree, lambda e: e.tag != "{namespace}element")
print ET.tostring(tree)

tree = ET.XML(DOC2)

# remove the entire 'element' elements

def fixup(e):
    if e.tag == "{namespace}element":
        e.clear()
        return False
    return True

cleanup(tree, fixup)
print ET.tostring(tree)