After reaching self._context.run then SIGTERM is called

Help
,
1

I want to Know what can be the possible reason for this warning and why sigterm is called

I am using python asyncio library

File "main1.py", line 107, in <module>
    main()
  File "main1.py", line 99, in main
    port=config.port):
  File "main1.py", line 60, in run_app
    loop.run_forever()
  File "/home/user/.pyenv/versions/3.7.4/lib/python3.7/asyncio/base_events.py", line 534, in run_forever
    self._run_once()
  File "/home/user/.pyenv/versions/3.7.4/lib/python3.7/asyncio/base_events.py", line 1771, in _run_once
    handle._run()
  File "/home/user/.pyenv/versions/3.7.4/lib/python3.7/asyncio/events.py", line 88, in _run
    self._context.run(self._callback, *self._args)
  File "main1.py", line 22, in handle_sigterm
    a()
  File "main1.py", line 13, in a
    traceback.print_stack()
Exception in callback handle_sigterm() at main1.py:20
handle: <Handle handle_sigterm() at main1.py:20>
Traceback (most recent call last):
  File "/home/user/.pyenv/versions/3.7.4/lib/python3.7/asyncio/events.py", line 88, in _run
    self._context.run(self._callback, *self._args)
  File "main1.py", line 26, in handle_sigterm
    raise exceptions.ResetException("Application exit requested via SIGTERM")
agents_common.exceptions.ResetException: Agent Error: Application exit requested via SIGTERM)