code: def _set_aws_environment(task: Task = None):
    current_zone = os.environ.get('NCLUSTER_ZONE', '')
    current_region = os.environ.get('AWS_DEFAULT_REGION', '')
    def log(*args):
      if task:
        task.log(*args)
      else:
        util.log(*args)
    if current_region and current_zone:
      assert current_zone.startswith(
        current_region), f'Current zone "{current_zone}" ($NCLUSTER_ZONE) is not ' \
                         f'in current region "{current_region} ($AWS_DEFAULT_REGION)'
      assert u.get_session().region_name == current_region
    if current_zone and not current_region:
      current_region = current_zone[:-1]
      os.environ['AWS_DEFAULT_REGION'] = current_region
    if not current_region:
      current_region = u.get_session().region_name
      if not current_region:
        log(f"No default region available, using {NCLUSTER_DEFAULT_REGION}")
        current_region = NCLUSTER_DEFAULT_REGION
      os.environ['AWS_DEFAULT_REGION'] = current_region
    log(f"Using account {u.get_account_number()}, region {current_region}, "
        f"zone {current_zone}")