code: def get_hostname():
      """Fetch the hostname using the callable from config or use `airflow.utils.net.getfqdn` as a fallback."""
      return conf.getimport(
          "core",
          "hostname_callable",
          fallback="airflow.utils.net.getfqdn",
      )()
  
imports: from __future__ import annotations
  import socket
  from functools import lru_cache
  from airflow.configuration import conf
label_desc: Use image node_id 3 for calling a global function with example usage: get_hostname() and returns: conf