如何在串口中生成随机负整数和正整数的文件？

import random
import serial

# 设置串口参数
ser = serial.Serial('/dev/ttyUSB0', 9600, timeout=1)

# 设置文件大小
file_size = 100

# 生成随机数并写入文件
with open('random_numbers.txt', 'w') as f:
    for i in range(file_size):
        num = random.randint(-100, 100)
        f.write(str(num) + '\n')

# 读取文件内容并发送到串口
with open('random_numbers.txt', 'r') as f:
    for line in f:
        ser.write(line.encode())