code: def onerror(function, path, excinfo):
      
      if not os.access(path, os.W_OK):
          # Is the error an access error?
          os.chmod(path, stat.S_IWUSR)
          function(path)
      else:
          raise
docs: Error handler for `shutil.rmtree`.
  
      If the error is due to an access error (read-only file), it
      attempts to add write permission and then retries.
      If the error is for another reason, it re-raises the error.
  
      Usage: `shutil.rmtree(path, onerror=onerror)