import re


def normalize_filename(filename):
    """
    Replace invalid for file names characters with string equivalents
    :param some_string: string to be converted to a valid file name
    :return: valid file name
    """
    not_allowed_pattern = r"[\[\]\/:*?\"\'<>|+\0\\\t\n\r\x0b\x0c]"
    filename = re.sub(not_allowed_pattern, ".", filename)
    return re.sub(r"\.{2,}", ".", filename)