The problem in Tf-idf.ipynb

[alexfeng2]

hi, when i run the 04.01-06 sample code,

Create the target column--True for Nightlife businesses, and False otherwise

twobiz_reviews['target'] = twobiz_reviews.apply(lambda x: 'Nightlife' in x['categories'],
axis=1)
there is a error:
"ValueError: Cannot set a frame with no defined index and a value that cannot be converted to a Series"
and i use the yelp dataset v13
how to solve this?