You don't have a "thing" named tokenizer. Review the hints section of the spec:
Odds are you’ll find nltk.tokenize.casual.TweetTokenizer of interest,
which can be used to tokenize a tweet (i.e., split it up into a list
of words) with code like:
tokenizer = nltk.tokenize.TweetTokenizer()
tokens = tokenizer.tokenize(tweet)
Are you sure it's adding a space, and you're not just printing a space using print? Consider
Added " so it's clear where the token begins and ends. Is there an extra space?
As per the spec [emphasis added]:
...among whose features is a tokenizer that you can use to split a tweet (which is maximally a 140-character str object) into a list of words (i.e., shorter str objects).
Program is trying to find a list of words in a list of words here if tokens in self.positives:. You want to test each word in tokens individually; you'...
I had the same problem. What worked for me was to clear cookies browsing history etc.. and then use incognito mode (ctrl+shift+n). Strangely this didn't work in just incognito mode I also needed to clear cookies/history.
Failing that switching to another browser worked for me. I'm on a linux system and I didn't have the same problems using Chromium.