docs: def _get_flatchoices(self):
          """
          Redefine standard method.
  
          Return constants themselves instead of their names for right rendering
          in admin's 'change_list' view, if field is present in 'list_display'
          attribute of model's admin.
          """
          return [
              (self.to_python(choice), value) for choice, value in self._choices
          ]