old_contents: from thread import _local
  
  BOOTSTRAP_2 = 'bootstrap-2'
  BOOTSTRAP_3 = 'bootstrap-3'
  
  
  def get_bootstrap_version():
      bootstrap_version = _local.BOOTSTRAP_VERSION
      if bootstrap_version is None:
          bootstrap_version = BOOTSTRAP_2
      return bootstrap_version
  
  
  def set_bootstrap_version3():
      _local.BOOTSTRAP_VERSION = BOOTSTRAP_3
  
  
  def set_bootstrap_version2():
      _local.BOOTSTRAP_VERSION = BOOTSTRAP_2
  
new_contents: import threading
  
  _thread_local = threading.local()
  
  BOOTSTRAP_2 = 'bootstrap-2'
  BOOTSTRAP_3 = 'bootstrap-3'
  
  
  def get_bootstrap_version():
      try:
          bootstrap_version = _thread_local.BOOTSTRAP_VERSION
      except AttributeError:
          bootstrap_version = BOOTSTRAP_2
      return bootstrap_version
  
  
  def set_bootstrap_version3():
      _thread_local.BOOTSTRAP_VERSION = BOOTSTRAP_3
  
  
  def set_bootstrap_version2():
      _thread_local.BOOTSTRAP_VERSION = BOOTSTRAP_2
  
subject: update thread local set / get for bootstrap version