How to import list from file?

[Epileptiker]

Hey, i've got a list inside a file like ["one", "two", "three"], which i'd like to import into my python script. I've tried it with
list1 = open("list1.txt", "r") but that didn't work. Could somebody help me with this please? I'm new to python and i just need to fix this one last problem.

This is the whole script.

import random, time, tweepy

list1 = open("list1.txt", "r")
list2 = open("list2.txt", "r")
list3 = open("list3.txt", "r")

def one():
    return random.choice(list1) + random.choice(list2)

def two():
    return random.choice(list2) + random.choice(list3)

#I'm working on a Twitter bot, that's just some twitter stuff down here 
consumer_key = 'XXX'
consumer_secret = 'XXX'
access_token = 'XXX'
access_token_secret = 'XXX'
auth = tweepy.OAuthHandler(consumer_key, consumer_secret)
auth.set_access_token(access_token, access_token_secret)
api = tweepy.API(auth)

while True:
    postthis = random.choice([one,two])()
    if len(postthis) <= 140:
        api.update_status(status=postthis)
        time.sleep(10)

And the error message:

Traceback (most recent call last):
  File "C:/Users/User/Desktop/Example/example.py", line 22, in <module>
    postthis = random.choice([one,two])()
  File "C:/Users/User/Desktop/Example/example.py", line 11, in two
    return random.choice(list2) + random.choice(list3)
  File "C:\Users\User\AppData\Local\Programs\Python\Python36-32\lib\random.py", line 256, in choice
    i = self._randbelow(len(seq))
TypeError: object of type '_io.TextIOWrapper' has no len()
>>>

I also don't understand the error has no len(). The content of my files are just very long lists, nothing else included. Maybe somebody has an alternative solution? Thanks so much :)