How can I loop this script every 30 seconds?

I want to loop this script every 30 seconds.

tweets = tweepy.Cursor(api.search_tweets, q='safe dev', lang='en', tweet_m开发者_如何学Pythonode='extended').items(100)
print(tweet.full_text, tweet.created_at)

I tried while true but it's not showing results.

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import time 


for index in range(0 , to_numbers_of_loops):
    #here you can define the time you want to run the script in your case 30 seconds 
    time.sleep(30)
    tweets = tweepy.Cursor(api.search_tweets, q='safe dev', lang='en', tweet_mode='extended').items(100)
    print(tweet.full_text, tweet.created_at)