code: def test_timezone_passes(self):
      assert validate_istimezone(self.timezoned) is None
  
imports: from __future__ import annotations
  from unittest import mock
  import pendulum
  import pytest
  from airflow.api_connexion.exceptions import BadRequest
  from airflow.api_connexion.parameters import check_limit, format_datetime, format_parameters, validate_istimezone
  from airflow.utils import timezone
  from tests.test_utils.config import conf_vars
label_desc: Use image node_id 3 for calling the TestValidateIsTimezone obj's underlying member method code with example usage: obj.test_timezone_passes() without return types