Bug in `most_common_interests_with(user)` method definition corrected

[mdusan]

Corrected most_common_interests_with(user) method definition is exactly the same as in the book (page8). The same result as the proposed correction would give a method which takes user_id = user["id"]argument instead of a dict type user argument. However, in that case the code that would be iterating through all the users to display the results would be less clean:

• For user argument:

  for user in users:
  print most_common_interests_with(user)

• For user_id argument:

  for user_id in range(len(users)):
  print most_common_interests_with(user_id)