tricircle cannot running as constants module coould not be imported

[ZhangChi]

root@ubuntu:~# sudo systemctl status <email address hidden>
● <email address hidden> - Devstack <email address hidden>
   Loaded: loaded (/<email address hidden>; enabled; vendor preset: enabled)
   Active: failed (Result: exit-code) since Tue 2020-03-24 15:05:22 UTC; 20min ago
  Process: 22803 ExecStart=/usr/local/bin/neutron-server --config-file /etc/neutron/neutron.conf.0 --config-file /etc/neutron/plugins/ml2/ml2_conf.ini (code=exited, status=1/FAILURE)
 Main PID: 22803 (code=exited, status=1/FAILURE)

Mar 24 15:05:22 ubuntu neutron-server[22803]: ERROR neutron File "/usr/local/lib/python3.6/dist-packages/paste/deploy/loadwsgi.py", line 25, in import_string
Mar 24 15:05:22 ubuntu neutron-server[22803]: ERROR neutron return ep.resolve()
Mar 24 15:05:22 ubuntu neutron-server[22803]: ERROR neutron File "/usr/local/lib/python3.6/dist-packages/pkg_resources/__init__.py", line 2451, in resolve
Mar 24 15:05:22 ubuntu neutron-server[22803]: ERROR neutron module = __import__(self.module_name, fromlist=['__name__'], level=0)
Mar 24 15:05:22 ubuntu neutron-server[22803]: ERROR neutron File "/opt/stack/tricircle/tricircle/common/request_source.py", line 14, in <module>
Mar 24 15:05:22 ubuntu neutron-server[22803]: ERROR neutron import constants as cons
Mar 24 15:05:22 ubuntu neutron-server[22803]: ERROR neutron ModuleNotFoundError: No module named 'constants'
Mar 24 15:05:22 ubuntu neutron-server[22803]: ERROR neutron
Mar 24 15:05:22 ubuntu systemd[1]: <email address hidden>: Main process exited, code=exited, status=1/FAILURE
Mar 24 15:05:22 ubuntu systemd[1]: <email address hidden>: Failed with result 'exit-code'.