code: def rand_str(num):
      """Generate random lowercase alphanumeric string of length num.
  
      :meta private:
      """
      return "".join(secrets.choice(alphanum_lower) for _ in range(num))
  
file_path: airflow/airflow/providers/cncf/kubernetes/kubernetes_helper_functions.py
imports: from __future__ import annotations
  import logging
  import secrets
  import string
  from typing import TYPE_CHECKING
  import pendulum
  from slugify import slugify
  from airflow.compat.functools import cache
  from airflow.configuration import conf
label_desc: Use image node_id 1 for calling a global function with example usage: rand_str(num) and returns: str