cannot import name 'NUMBER_TUPLE' from 'lingua_franca.format'

[logtheta]

-Raspberry 4 B 4GB
-Image: Picroft_Buster-Keaton_2020-01-10, ver Buster Keaton - Pork Pi

Mycroft does not start and this is the error:

In a few moments you will see the Mycroft CLI (command line interface).
Hit Ctrl+C to return to the Linux command line. You can launch the CLI
again by entering: mycroft-cli-client

Already up to date.
Initializing...
Starting background service bus
CAUTION: The Mycroft bus is an open websocket with no built-in security
measures. You are responsible for protecting the local port
8181 with a firewall as appropriate.
Starting background service skills
Starting cli
Traceback (most recent call last):
File "/usr/lib/python3.7/runpy.py", line 183, in _run_module_as_main
mod_name, mod_spec, code = _get_module_details(mod_name, _Error)
File "/usr/lib/python3.7/runpy.py", line 109, in _get_module_details
import(pkg_name)
File "/home/pi/mycroft-core/mycroft/init.py", line 17, in
from mycroft.api import Api
File "/home/pi/mycroft-core/mycroft/api/init.py", line 22, in
from mycroft.configuration import Configuration
File "/home/pi/mycroft-core/mycroft/configuration/init.py", line 15, in
from .config import Configuration, LocalConf, RemoteConf
File "/home/pi/mycroft-core/mycroft/configuration/config.py", line 23, in
from mycroft.util.json_helper import load_commented_json, merge_dict
File "/home/pi/mycroft-core/mycroft/util/init.py", line 38, in
from mycroft.util.format import nice_number
File "/home/pi/mycroft-core/mycroft/util/format.py", line 34, in
from lingua_franca.format import (NUMBER_TUPLE, DateTimeFormat, join_list,
ImportError: cannot import name 'NUMBER_TUPLE' from 'lingua_franca.format' (/home/pi/mycroft-core/.venv/lib/python3.7/site-packages/lingua_franca/format.py)

Any ideas?

Thanks!