<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def unregister_finders():
 """Unregister finders necessary for PEX to function properly."""


  global __PREVIOUS_FINDER
  if not __PREVIOUS_FINDER:
    return

  pkg_resources.register_finder(zipimport.zipimporter, __PREVIOUS_FINDER)
  _remove_finder(pkgutil.ImpImporter, find_wheels_on_path)

  if importlib_machinery is not None:
    _remove_finder(importlib_machinery.FileFinder, find_wheels_on_path)

  __PREVIOUS_FINDER = None