Python write to file and read from file

import uuid
import datetime
import timedef get_uuid_time():return (f"{uuid.uuid4().hex}_____{datetime.datetime.now().strftime("%Y%m%d%H%M%S%f")}")def get_time():return (f"{datetime.datetime.now().strftime("%Y%m%d%H%M%S%f")}")try:fileName="WriteTest.txt"idx=0with open(fileName,"a+") as writeFile:    startTime=datetime.datetime.now()while idx<100000001:idx=idx+1writeFile.write(f"{idx}_{get_uuid_time()}\n")if idx%1000000==0:totalCost=f"{(datetime.datetime.now()-startTime).total_seconds():.2f}"print(f"idx:{idx},cost:{totalCost} seconds")print(f"idx:{idx},cost:{totalCost} seconds")except Exception as ex:print(ex)