old_contents: 
  from ..filters import *
  from ..widgets import BooleanWidget
  
  
  class BooleanFilter(BooleanFilter):
      def __init__(self, *args, **kwargs):
          kwargs.setdefault('widget', BooleanWidget)
  
          super().__init__(*args, **kwargs)
  
new_contents: 
  from ..filters import BooleanFilter as _BooleanFilter
  from ..filters import *
  from ..widgets import BooleanWidget
  
  
  class BooleanFilter(_BooleanFilter):
      def __init__(self, *args, **kwargs):
          kwargs.setdefault('widget', BooleanWidget)
  
          super().__init__(*args, **kwargs)
  
subject: Fix mypy error: circular inheritance