Edit example code
The original code forget to import the `random` module and the `EntityRecognizer` module.
@@ -138,7 +138,9 @@ p
+code.
import spacy
+ import random
from spacy.gold import GoldParse
+ from spacy.language import EntityRecognizer
train_data = [
('Who is Chaka Khan?', [(7, 17, 'PERSON')]),
