old_contents: # This code is borrowed from mesonbuild.mesonlib
  # https://github.com/mesonbuild/meson/blob/master/mesonbuild/mesonlib.py
  
  import os
  import stat
  import shutil
  import time
  
  
  def _make_tree_writable(topdir):
      # Ensure all files and directories under topdir are writable
      # (and readable) by owner.
      for d, _, files in os.walk(topdir):
          os.chmod(d, os.stat(d).st_mode | stat.S_IWRITE | stat.S_IREAD)
          for fname in files:
              fpath = os.path.join(d, fname)
              if os.path.isfile(fpath):
                  mode = os.stat(fpath).st_mode | stat.S_IWRITE | stat.S_IREAD
                  os.chmod(fpath, mode)
  
  
  def windows_proof_rmtree(f):
      # On Windows if anyone is holding a file open you can't
      # delete it. As an example an anti virus scanner might
      # be scanning files you are trying to delete. The only
      # way to fix this is to try again and again.
      delays = [0.1, 0.1, 0.2, 0.2, 0.2, 0.5, 0.5, 1, 1, 1, 1, 2]
      # Start by making the tree wriable.
      _make_tree_writable(f)
      for d in delays:
          try:
              shutil.rmtree(f)
              return
          except FileNotFoundError:
              return
          except (OSError, PermissionError):
              time.sleep(d)
      # Try one last time and throw if it fails.
      shutil.rmtree(f)
  
new_contents: # This code is borrowed from mesonbuild.mesonlib
  # https://github.com/mesonbuild/meson/blob/master/mesonbuild/mesonlib.py
  
  import os
  import stat
  import shutil
  import time
  
  
  def _make_tree_writable(topdir):
      # Ensure all files and directories under topdir are writable
      # (and readable) by owner.
      for d, _, files in os.walk(topdir):
          os.chmod(d, os.stat(d).st_mode | stat.S_IWRITE | stat.S_IREAD)
          for fname in files:
              fpath = os.path.join(d, fname)
              if os.path.isfile(fpath):
                  mode = os.stat(fpath).st_mode | stat.S_IWRITE | stat.S_IREAD
                  os.chmod(fpath, mode)
  
  
  def windows_proof_rmtree(f):
      # On Windows if anyone is holding a file open you can't
      # delete it. As an example an anti virus scanner might
      # be scanning files you are trying to delete. The only
      # way to fix this is to try again and again.
      delays = [0.1, 0.1, 0.2, 0.2, 0.2, 0.5, 0.5, 1, 1, 1, 1, 2]
      # Start by making the tree writable.
      _make_tree_writable(f)
      for d in delays:
          try:
              shutil.rmtree(f)
              return
          except FileNotFoundError:
              return
          except (OSError, PermissionError):
              time.sleep(d)
      # Try one last time and throw if it fails.
      shutil.rmtree(f)
  
subject: Fix typo