AttributeError listing taskmanager pools

Jun 10 13:39:46 uwsgi: Traceback (most recent call last):
  File "/usr/lib/python3.8/site-packages/django/core/handlers/base.py", line 113, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/usr/lib/python3.8/site-packages/django/views/decorators/csrf.py", line 54, in wrapped_view
    return view_func(*args, **kwargs)
  File "/usr/lib/python3.8/site-packages/rest_framework/viewsets.py", line 114, in view
    return self.dispatch(request, *args, **kwargs)
  File "/usr/lib/python3.8/site-packages/rest_framework/views.py", line 505, in dispatch
    response = self.handle_exception(exc)
  File "/usr/lib/python3.8/site-packages/rest_framework/views.py", line 465, in handle_exception
    self.raise_uncaught_exception(exc)
  File "/usr/lib/python3.8/site-packages/rest_framework/views.py", line 476, in raise_uncaught_exception
    raise exc
  File "/usr/lib/python3.8/site-packages/rest_framework/views.py", line 502, in dispatch
    response = handler(request, *args, **kwargs)
  File "/usr/lib/python3.8/site-packages/rest_framework/mixins.py", line 43, in list
    return self.get_paginated_response(serializer.data)
  File "/usr/lib/python3.8/site-packages/rest_framework/serializers.py", line 760, in data
    ret = super().data
  File "/usr/lib/python3.8/site-packages/rest_framework/serializers.py", line 260, in data
    self._data = self.to_representation(self.instance)
  File "/usr/lib/python3.8/site-packages/rest_framework/serializers.py", line 677, in to_representation
    return [
  File "/usr/lib/python3.8/site-packages/rest_framework/serializers.py", line 678, in <listcomp>
    self.child.to_representation(item) for item in iterable
  File "/srv/FuzzManager/server/taskmanager/serializers.py", line 14, in to_representation
    ret["cycle_time"] = int(instance.cycle_time.total_seconds())
AttributeError: 'NoneType' object has no attribute 'total_seconds'