docs: def get_db_prep_save(self, value, connection=None):
          """
          Returns field's value prepared for saving into a database.
          """
          ## convert to settings.TIME_ZONE
          if value is not None:
              if value.tzinfo is None:
                  value = default_tz.localize(value)
              else:
                  value = value.astimezone(default_tz)
          return super(LocalizedDateTimeField, self).get_db_prep_save(value, connection=connection)