code: def run(
      principal: str | None,
      keytab: str,
      mode: KerberosMode = KerberosMode.STANDARD,
  ):
      """
      Run the kerberos renewer.
  
      :param principal: principal name
      :param keytab: keytab file
      :param mode: mode to run the airflow kerberos in
      :return: None
      """
      if not keytab:
          log.warning(
              "Keytab renewer not starting, no keytab configured"
          )
          sys.exit(0)
  
      log.info("Using airflow kerberos with mode: %s", mode.value)
  
      if mode == KerberosMode.STANDARD:
          while True:
              renew_from_kt(principal, keytab)
              time.sleep(conf.getint("kerberos", "reinit_frequency"))
      elif mode == KerberosMode.ONE_TIME:
          renew_from_kt(principal, keytab)
  
file_path: airflow/airflow/security/kerberos.py
imports: from __future__ import annotations
  from enum import Enum
  import logging
  import shlex
  import subprocess
  import sys
  import time
  from airflow.configuration import conf
  from airflow.utils.net import get_hostname
label_desc: Use image node_id 5 for calling a global function with example usage: run(principal, keytab, mode) without return types