regex [] and "timestamp":"

import re
hand = open('text.txt')
for line in hand:
    line = line.rstrip()
    error_message = re.findall('^\[(.+?)\]', line)
    time_stamp = re.findall('"timestamp":"(.+)', line)


    if len(error_message) > 0:
        print(f"error message: {error_message[0]}, timestamp: {time_stamp[0]}")