docs: def chmod(path, mode, operator='=', recursive=False):
      '''
      Change file mode bits.
  
      When recursively chmodding a directory, executable bits in ``mode`` are
      ignored when applying to a regular file. E.g. ``chmod(path, mode=0o777,
      recursive=True)`` would apply ``mode=0o666`` to regular files.
  
      Symlinks are ignored.
  
      Parameters
      ----------
      path : ~pathlib.Path
          Path to chmod.
      mode : int
          Mode bits to apply, e.g. ``0o777``.
      operator : str
          How to apply the mode bits to the file, one of:
  
          '='
              Replace mode with given mode.
          '+'
              Add to current mode.
          '-'
              Subtract from current mode.
  
      recursive : bool
          Whether to chmod recursively.
      '''
      if mode > 0o777 and operator != '=':
          raise ValueError('Special bits (i.e. >0o777) only supported when using "=" operator')
  
      # first chmod path
      if operator == '+':
          mode_ = path.stat().st_mode | mode
      elif operator == '-':
          mode_ = path.stat().st_mode & ~mode
      else:
          mode_ = mode
      if path.is_symlink():
          # Do not chmod or follow symlinks
          return
      path.chmod(mode_)
  
      # then its children
      def chmod_children(parent, files, mode_mask, operator):
          for file in files:
              with suppress(FileNotFoundError):
                  file = parent / file
                  if not file.is_symlink():
                      chmod(file, mode & mode_mask, operator)
      if recursive and path.is_dir():
          for parent, dirs, files in os.walk(str(path)):
              parent = Path(parent)
              chmod_children(parent, dirs, 0o777777, operator)
              chmod_children(parent, files, 0o777666, operator)