FlatDict "leaf" nodes in output of as_dict()

[jpo-tu]

version info:

$ python --version
Python 3.12.1
$ pip show flatdict
Name: flatdict
Version: 4.0.1
Summary: Python module for interacting with nested dicts as a single level dict with delimited keys.
Home-page: https://github.com/gmr/flatdict
Author: Gavin M. Roy
Author-email: gavinmroy@gmail.com
License: BSD 3-Clause License
Location: /usr/local/python/3.12.1/lib/python3.12/site-packages
Requires: 
Required-by:

Summary: as_dict() returns empty "leaf" dicts as FlatDict instances if key path contains an odd number of segments

Reproduce:

from flatdict import FlatDict
print(FlatDict({'a': {}}).as_dict())

Expected output:

{'a': {}}

Actual output:

{'a': <FlatDict id=139946220524928 {}>"}

If the key path contains an even number of segments the issue is not present:

from flatdict import FlatDict

FlatDict({'a': {}}).as_dict()
# {'a': <FlatDict id=140045793698368 {}>"}

FlatDict({'a': {'b': {}}}).as_dict()
# {'a': {'b': {}}}

FlatDict({'a': {'b': {'c': {}}}}).as_dict()
# {'a': {'b': {'c': <FlatDict id=140045792487056 {}>"}}}

FlatDict({'a': {'b': {'c': {'d':{}}}}}).as_dict()
# {'a': {'b': {'c': {'d': {}}}}}

# various, etc

Other information:

• I also tested with flatdict==3.4.0 and python 3.9 and the issue is present