Flask -如何将datetime JSON数据从API调用转换为“最后一次看到X小时/分钟前”？

from datetime import datetime
import json

datetime_str = "2022-01-01 12:00:00"  # 假设从API获取的datetime字符串
datetime_obj = datetime.strptime(datetime_str, "%Y-%m-%d %H:%M:%S")

current_datetime = datetime.now()
time_diff = current_datetime - datetime_obj

if time_diff.days > 0:
    time_ago = f"最后一次看到{time_diff.days}天前"
elif time_diff.seconds >= 3600:
    hours = time_diff.seconds // 3600
    time_ago = f"最后一次看到{hours}小时前"
else:
    minutes = time_diff.seconds // 60
    time_ago = f"最后一次看到{minutes}分钟前"

response_data = {"time_ago": time_ago}
response_json = json.dumps(response_data)
return response_json