old_contents: """
  Ensure that the local copy of distutils is preferred over stdlib.
  
  See https://github.com/pypa/setuptools/issues/417#issuecomment-392298401
  for more motivation.
  """
  
  import sys
  import importlib
  from os.path import dirname
  
  
  sys.path.insert(0, dirname(dirname(__file__)))
  importlib.import_module('distutils')
  sys.path.pop(0)
  
new_contents: """
  Ensure that the local copy of distutils is preferred over stdlib.
  
  See https://github.com/pypa/setuptools/issues/417#issuecomment-392298401
  for more motivation.
  """
  
  import sys
  import importlib
  import contextlib
  from os.path import dirname
  
  
  @contextlib.contextmanager
  def patch_sys_path():
      orig = sys.path[:]
      sys.path[:] = [dirname(dirname(__file__))]
      try:
          yield
      finally:
          sys.path[:] = orig
  
  
  if 'distutils' in sys.path:
      raise RuntimeError("Distutils must not be imported before setuptools")
  
  
  with patch_sys_path():
      importlib.import_module('distutils')
  
subject: Update distutils patch to monkeypatch all paths from sys.path to ensure that distutils is never imported except from the same path as setuptools. Assert that 'distutils' is not already in sys.modules.