Supplement to Stackoverflow answer http://stackoverflow.com/questions/42774573/python-function-for-xml-list/42786367

xml_list_answer.py

import json
from xml.etree import ElementTree


tree = ElementTree.parse('raml20.xml')

ns = {'ns': 'raml20.xsd'}
nsP, nsList, nsItem = ('{%s}%s' % (ns['ns'], i) for i in ('p', 'list', 'item'))


def pkv(o):
    """Return dict with name:text of p elements"""
    return {k.attrib['name']: k.text for k in o.iter(nsP)}


def parse(tree):
    root = tree.getroot()
    objs = {}
    for mo in root.findall('./ns:cmData/ns:managedObject', ns):
        obj = pkv(mo)
        for i in mo.iter(nsList):
            obj[i.attrib['name']] = [pkv(j) for j in i.iter(nsItem)]
        objs[mo.attrib['distName']] = obj
    return objs


def diff_dicts(d1, d2, ignore_keys=set()):
    """Return dict with differences between the dicts provided as arguments"""
    k1 = set(d1.keys())
    k2 = set(d2.keys())
    diff = {}
    diff.update(
        {i: (d1[i], d2[i]) for i in (k1 & k2) - ignore_keys if d1[i] != d2[i]})
    diff.update({i: (d1.get(i), d2.get(i)) for i in (k1 ^ k2) - ignore_keys})
    return diff


def diff_lists(l1, l2):
    """Return dict with differences between lists of dicts provided as arguments"""
    diff = {}
    # note: assumes that lists are of same length
    for i, (d1, d2) in enumerate(zip(l1, l2)):
        d = diff_dicts(d1, d2)
        if d:
            diff[i] = d
    return diff


def diff_objects(o1, o2):
    """Return dict with differences between two objects (dicts) provided as arguments"""
    listkeys = set(
        i for o in (o1, o2) for i in o if isinstance(o.get(i), list))
    diff = diff_dicts(o1, o2, listkeys)
    for i in listkeys:
        if i in o1 and i in o2:
            diff.update({i: diff_lists(o1[i], o2[i])})
        else:
            diff.update({i: (o1.get(i), o2.get(i))})
    return diff


def compare_objects(reference, objs):
    diffs = []
    for k, o in objs.items():
      diff = diff_objects(reference, o)
      if diff:
          diffs.append((k, diff))
    return diffs


reference = ...  # set your reference object here
res = compare_objects(reference, parse(tree))
print(json.dumps(res, indent=2))