from typing import Union
import re


def normalize_regripper_files(path_str: Union[str, None]) -> Union[str, None]:
    """
    Normalizes a path string removing timestamps from regripper files.
    Args:
        path_str: The original path string.

    Returns: The path string where timestamps are removed from regripper paths.

    """
    # takes a file name like "regripper-12345-full" and removes the id to become "regripper-full"
    return None if path_str is None else re.sub(r'regripper-[0-9]+-full', 'regripper-full', path_str)