如何将YYYYMMDDHHMMSS转换为'date`可读的日期

import datetime

def convert_to_readable_date(timestamp):
    try:
        date_str = str(timestamp)
        year = int(date_str[0:4])
        month = int(date_str[4:6])
        day = int(date_str[6:8])
        hour = int(date_str[8:10])
        minute = int(date_str[10:12])
        second = int(date_str[12:14])
        dt = datetime.datetime(year, month, day, hour, minute, second)
        return dt.strftime('%Y-%m-%d %H:%M:%S')
    except ValueError:
        return "Invalid timestamp format"

timestamp = '20211231120000'
readable_date = convert_to_readable_date(timestamp)
print(readable_date)