How to make a nested dictionary and dynamically append data

Question

I have a loop giving me three variables

matteGroup
matteName
object

I would like to make a nested dicionary holding all the data like:

Answer 1

try something like this

dizGroup = {}

for obj in mc.ls(type='transform'):
    if mc.objExists(obj + ('.matteGroup')):
        matteGroup = mc.getAttr(obj + ('.matteGroup'))
        matteName = mc.getAttr(obj + ('.matteName'))

        if matteGroup not in dizGroup:
            dizGroup[matteGroup] = {}

        if matteName not in dizGroup[matteGroup]:
            dizGroup[matteGroup][matteName] = []

        dizGroup[matteGroup][matteName].append(obj)