Taking into account the following code:
def recommend(username, users): nearest = computeNearestNeighbor(username, users) recommendations =  neighborRatings = users[nearest] userRatings = users[username] for artist in neighborRatings: if not artist in userRatings: recommendations.append((artist,neighborRatings[artist])) return recommendations
The computer codeNearestNeighbor:
def computeNearestNeighbor(username,users): """creates a sorted list of users based on their distance to username""" distances =  for user in users: if user!=username: distance = manhattan(users[user],users[username]) distances.append((distance, user)) # Sort based on the distance -- closest first distances.sort() return distances
Could you tell me what the two brackets
 do, then this sentence?
nearest = computeNearestNeighbor(username, users)