I want to know the answer to the following question:
How many years did NBC Sports receive an extension for with the Premier League in 2015?
All the background I'm provided with is that "NBC Sports reached a six-year extension with the Premier League in 2015 to broadcast the league through the 2021–22 season in a deal valued at $1 billion (£640 million).". Is that enough to answer the question?
Answer: yes