useful_collections - реализиация ImmutableDict и LockableDict

>>> from useful_collections.dict import ImmutableDict
>>> my_immutable_dict = ImmutableDict(key='immutable val')

# accessing dict item
>>> my_immutable_dict['key']
'immutable val'

# accessing dict item as attribute
>>> my_immutable_dict.key
'immutable val'

# trying to override dict value
>>> my_immutable_dict['key'] = 'new value'
Traceback (most recent call last):
  ...
useful_collections.dict.ForbiddenSetItem: __setitem__ method is forbidden for ImmutableDict objects

>>> my_immutable_dict.key = 'try again'
Traceback (most recent call last):
  ...
useful_collections.dict.ForbiddenSetAttr: __setattr__ method is forbidden for ImmutableDict objects