ModuleNotFoundError: No module named 'spns.core'

[itsazzad]

$ sudo journalctl -xeu spns-hivemind.service
░░ Support: http://www.ubuntu.com/support
░░
░░ A start job for unit spns-hivemind.service has begun execution.
░░
░░ The job identifier is 99353.
Nov 10 21:39:38 vps-b0b0ebac python3[43662]: Traceback (most recent call last):
Nov 10 21:39:38 vps-b0b0ebac python3[43662]: File "", line 198, in _run_module_as_main
Nov 10 21:39:38 vps-b0b0ebac python3[43662]: File "", line 88, in _run_code
Nov 10 21:39:38 vps-b0b0ebac python3[43662]: File "/home/ubuntu/session-push-notification-server/spns/hivemind.py", line 1, in
Nov 10 21:39:38 vps-b0b0ebac python3[43662]: from .core import HiveMind, logger as core_logger
Nov 10 21:39:38 vps-b0b0ebac python3[43662]: ModuleNotFoundError: No module named 'spns.core'
Nov 10 21:39:38 vps-b0b0ebac systemd[1]: spns-hivemind.service: Main process exited, code=exited, status=1/FAILURE
░░ Subject: Unit process exited
░░ Defined-By: systemd
░░ Support: http://www.ubuntu.com/support
░░
░░ An ExecStart= process belonging to unit spns-hivemind.service has exited.
░░
░░ The process' exit code is 'exited' and its exit status is 1.
Nov 10 21:39:38 vps-b0b0ebac systemd[1]: spns-hivemind.service: Failed with result 'exit-code'.
░░ Subject: Unit failed
░░ Defined-By: systemd
░░ Support: http://www.ubuntu.com/support
░░
░░ The unit spns-hivemind.service has entered the 'failed' state with result 'exit-code'.
Nov 10 21:39:38 vps-b0b0ebac systemd[1]: Failed to start Session Push Notification Server -- central push handler (hivemind).
░░ Subject: A start job for unit spns-hivemind.service has failed
░░ Defined-By: systemd
░░ Support: http://www.ubuntu.com/support
░░
░░ A start job for unit spns-hivemind.service has finished with a failure.
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░░ The job identifier is 99353 and the job result is failed.
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