def on_mismatch(self, pair):
        """Called for pairs that don't match `match` and `exclude` filters.

        If --delete-unmatched is on, remove the remote resource.
        """
        remote_entry = pair.remote
        if self.options.get("delete_unmatched") and remote_entry:
            self._log_action("delete", "unmatched", ">", remote_entry)
            if remote_entry.is_dir():
                self._remove_dir(remote_entry)
            else:
                self._remove_file(remote_entry)
        else:
            self._log_action("skip", "unmatched", "-", pair.any_entry, min_level=4)