content: import ctypes
  import random
  import string
  
  
  def get_random_string(length=15):
      """Get random string with letters and digits.
  
      Args:
          length (int): Length of random string. Default: 15.
      """
      return ''.join(
          random.choice(string.ascii_letters + string.digits)
          for _ in range(length))
  
  
  def get_thread_id():
      """Get current thread id."""
      # use ctype to find thread id
      thread_id = ctypes.CDLL('libc.so.6').syscall(186)
      return thread_id
  
  
  def get_shm_dir():
      """Get shm dir for temporary usage."""
      return '/dev/shm'
  