AttributeError: 'NoneType' object has no attribute 'split'

[Artem3335]

import vk_api, random
from TestBot.plugins import system, functions
from vk_api.bot_longpoll import VkBotLongPoll, VkBotEventType

vk, longpoll = system.session()

while True:
for event in longpoll.listen():
if event.type == VkBotEventType.MESSAGE_NEW:
message = event.obj.text.split()
print(event.obj.peer_id)