docs: def get_filter(self, **filter_kwargs):
          """
          Combines the Q objects returned by a valid
          filter form with any other arguments and
          returns a list of Q objects that can be passed
          to a queryset.
          """
  
          q_objects = super(ListView, self).get_filter(**filter_kwargs)
          form = self.get_filter_form()
          if form:
              q_objects.extend(form.get_filter())
  
          return q_objects