(env) dag@cricket:~/tinydb-test$ pip freeze
pkg-resources==0.0.0
tinydb==4.0.0
tinydb-serialization==1.0.4

Python 3.7.5 (default, Nov 7 2019, 10:50:52)
[GCC 8.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.

import tinydb
from tinydb_serialization import SerializationMiddleware
Traceback (most recent call last):
File "", line 1, in
File "/home/dag/tinydb-test/env/lib/python3.7/site-packages/tinydb_serialization/init.py", line 6, in
from tinydb.utils import with_metaclass
ImportError: cannot import name 'with_metaclass' from 'tinydb.utils' (/home/dag/tinydb-test/env/lib/python3.7/site-packages/tinydb/utils.py)