Django-filter: TypeError:python 3.5에서 odict_items 객체를 피클할 수 없습니다.

안녕하세요, python>=3.5에서 FilterSet 파생 클래스를 인스턴스화하는 동안 오류가 발생했습니다. 3.4에서는 모든 것이 정상적으로 작동합니다.

File "/home/dan/venvs/notes3.5/lib/python3.5/site-packages/django_filters/filterset.py" in __init__
  291.         self.filters = copy.deepcopy(self.base_filters)

File "/home/dan/venvs/notes3.5/lib/python3.5/copy.py" in deepcopy
  182.                 y = _reconstruct(x, rv, 1, memo)

File "/home/dan/venvs/notes3.5/lib/python3.5/copy.py" in _reconstruct
  320.                 value = deepcopy(value, memo)

File "/home/dan/venvs/notes3.5/lib/python3.5/copy.py" in deepcopy
  182.                 y = _reconstruct(x, rv, 1, memo)

File "/home/dan/venvs/notes3.5/lib/python3.5/copy.py" in _reconstruct
  297.             state = deepcopy(state, memo)

File "/home/dan/venvs/notes3.5/lib/python3.5/copy.py" in deepcopy
  155.         y = copier(x, memo)

File "/home/dan/venvs/notes3.5/lib/python3.5/copy.py" in _deepcopy_dict
  243.         y[deepcopy(key, memo)] = deepcopy(value, memo)

File "/home/dan/venvs/notes3.5/lib/python3.5/copy.py" in deepcopy
  155.         y = copier(x, memo)

File "/home/dan/venvs/notes3.5/lib/python3.5/copy.py" in _deepcopy_dict
  243.         y[deepcopy(key, memo)] = deepcopy(value, memo)

File "/home/dan/venvs/notes3.5/lib/python3.5/copy.py" in deepcopy
  174.                         rv = reductor(4)

Exception Type: TypeError at /notes/
Exception Value: can't pickle odict_items objects

내 FilterSet 클래스의 예. DateTimeFIlter 및 CommaSeparatedCharFilter 필드는 사용자 정의입니다.

class NoteListFilterset(django_filters.FilterSet):
    strict = STRICTNESS.RAISE_VALIDATION_ERROR

    keywords = CommaSeparatedCharFilter(name='keyword', lookup_expr='in')
    datetime_from = DateTimeFilter(name='datetime', lookup_expr='gte')
    datetime_to = DateTimeFilter(name='datetime', lookup_expr='lte')
    get_hidden = django_filters.MethodFilter(method='filter_by_get_hidden')