# File lib/twitter/rest/friends_and_followers.rb, line 106
      def follow(*args)
        arguments = Twitter::Arguments.new(args)
        existing_friends = Thread.new do
          friend_ids.to_a
        end
        new_friends = Thread.new do
          users(args).collect(&:id)
        end
        follow!(new_friends.value - existing_friends.value, arguments.options)
      end