code: def get_kerberos_principle(principal: str | None) -> str:
      """Retrieve Kerberos principal. Fallback to principal from Airflow configuration if not provided."""
      return principal or conf.get_mandatory_value(
          "kerberos", "principal"
      ).replace("_HOST", get_hostname())
  
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 1 for calling a global function with example usage: get_kerberos_principle(principal) and returns: unknown