Where to find similarity.normalized_levenshtein

[eclipse-du]

i can not install similarity with pip3, and i don't find any code related to string_similarity_features function, does this function really matter?
3q

[Sheldon1999]

I have successfully installed it using pip3 by simple command:
pip3 install semantic-text-similarity
Yet it took a lot of time because of a lot of dependencies. and Yes, it matters. The author has clearly used this in examples to import models. (example1, example2)