code: def read(self, include_deleted=False):
          
          if is_soft_delete() and not include_deleted:
              return self.filter(unread=False, deleted=False)
  
          # When SOFT_DELETE=False, developers are supposed NOT to touch 'deleted' field.
          # In this case, to improve query performance, don't filter by 'deleted' field
          return self.filter(unread=False)
docs: Return only read items in the current queryset