How to use the munch.DefaultMunch function in munch

from munch import Munch, DefaultMunch
import copy

root = os.path.join(os.path.dirname(__file__), '..')

def load(url):
  with urllib.request.urlopen(url) as f:
    return json.loads(f.read().decode())

data = DefaultMunch.fromDict({
  'zotero': load('https://api.zotero.org/schema'),
  'jurism': load('https://raw.githubusercontent.com/Juris-M/zotero-schema/master/schema-jurism.json')
}, None)

print('Generating item field metadata...')
ValidFields = DefaultMunch(None, {})
ValidTypes = {}
Alias = {}
Itemfields = set()
for client in data.keys():
  for spec in data[client].itemTypes:
    if spec.itemType in ValidTypes:
      ValidTypes[spec.itemType] = 'true'
    else:
      ValidTypes[spec.itemType] = client

    if not ValidFields[spec.itemType]:
      if spec.itemType == 'note':
        ValidFields[spec.itemType] = DefaultMunch(None, {field: 'true' for field in 'itemType tags note id itemID dateAdded dateModified'.split(' ')})
      elif spec.itemType == 'attachment':
        ValidFields[spec.itemType] = DefaultMunch(None, {field: 'true' for field in 'itemType tags id itemID dateAdded dateModified'.split(' ')})
      else:

print('Generating item field metadata...')
ValidFields = DefaultMunch(None, {})
ValidTypes = {}
Alias = {}
Itemfields = set()
for client in data.keys():
  for spec in data[client].itemTypes:
    if spec.itemType in ValidTypes:
      ValidTypes[spec.itemType] = 'true'
    else:
      ValidTypes[spec.itemType] = client

    if not ValidFields[spec.itemType]:
      if spec.itemType == 'note':
        ValidFields[spec.itemType] = DefaultMunch(None, {field: 'true' for field in 'itemType tags note id itemID dateAdded dateModified'.split(' ')})
      elif spec.itemType == 'attachment':
        ValidFields[spec.itemType] = DefaultMunch(None, {field: 'true' for field in 'itemType tags id itemID dateAdded dateModified'.split(' ')})
      else:
        ValidFields[spec.itemType] = DefaultMunch(None, {field: 'true' for field in 'itemType creators tags attachments notes seeAlso id itemID dateAdded dateModified multi'.split(' ')})

    for field in spec.fields:
      if field.baseField:
        if not field.baseField in Alias: Alias[field.baseField] = Munch(zotero=set(), jurism=set())
        Alias[field.baseField][client].add(field.field)

        fieldName = field.baseField
      else:
        fieldName = field.field

      if spec.itemType not in ['note', 'attachment']: Itemfields.add(fieldName)

Alias = {}
Itemfields = set()
for client in data.keys():
  for spec in data[client].itemTypes:
    if spec.itemType in ValidTypes:
      ValidTypes[spec.itemType] = 'true'
    else:
      ValidTypes[spec.itemType] = client

    if not ValidFields[spec.itemType]:
      if spec.itemType == 'note':
        ValidFields[spec.itemType] = DefaultMunch(None, {field: 'true' for field in 'itemType tags note id itemID dateAdded dateModified'.split(' ')})
      elif spec.itemType == 'attachment':
        ValidFields[spec.itemType] = DefaultMunch(None, {field: 'true' for field in 'itemType tags id itemID dateAdded dateModified'.split(' ')})
      else:
        ValidFields[spec.itemType] = DefaultMunch(None, {field: 'true' for field in 'itemType creators tags attachments notes seeAlso id itemID dateAdded dateModified multi'.split(' ')})

    for field in spec.fields:
      if field.baseField:
        if not field.baseField in Alias: Alias[field.baseField] = Munch(zotero=set(), jurism=set())
        Alias[field.baseField][client].add(field.field)

        fieldName = field.baseField
      else:
        fieldName = field.field

      if spec.itemType not in ['note', 'attachment']: Itemfields.add(fieldName)

      if ValidFields[spec.itemType][fieldName]:
        ValidFields[spec.itemType][fieldName] = 'true'
      else:
        ValidFields[spec.itemType][fieldName] = client