How do I delete most keys in a json file using python?

I have a json file with all the data I searched using Twitter API. I only want to keep certain keys in that file and delete the rest of them, but don't know how to do it correctly. I wrote some code to do so, but I get the error "list indices must be integers or slices, not str"

import json

def read_json(json_file:str)->list:
    tweets_data=[]
    for tweet in open(json_file, 'r'):
        tweets_data.append(json.loads(tweet))
    return tweets_data
tags = ["created_at", "full_text"]
tweet_list=read_json('test.json')

for i in tweet_list["tweet"].keys():
    if i not in tags:
        del tweet_list["tweet"][i]
        
print (tweet_list[0])

def read_json(json_file:str)->list:
    tweets = []
    with open(json_file, 'r') as f:
        for line in f:
            tweets.append(json.loads(line))
    return tweets
tags = ['created_at', 'full_text']
tweets = read_json('tweets.json')
for tweet in tweets:
    for key in list(tweet.keys()):
        if key not in tags:
            del tweet[key]