Ruby class variable

I am trying to learn Ruby by reading tutorials on Class Variables.

The code creates a "Worker" object, a class variable is created to keep track of which instance of Worker was created by the user last.

I have copied the code from the author but I get the error:

undefined method `latest' for Worker:Class (NoMethodError)

The code I have found is:

class Worker
  attr_writer :number_of_jobs

  def initialize(name, job)
    @name = name
    @job = job

    @@latest = @name
    @@job = @job
    puts "Lets get started"
  end

  def new_job(job)
    @job = job
    puts "I moved to #{job}!"
    self.fetch_info
  end

  def name_update(name_new)
    @name = name_new
    puts "My new name is #{name_new}."
    self.fetch_info
  end

  def fetch_info
    puts "I'm #{@name} in #{@location}."
  end

  def job_score
    return "#{@number_of_jobs * 10}Fg"
  end


  protected
  def are_you_worker?(guest_name)
    puts "Yes #{guest_name}, I am a worker!"
    return true
  end

  private
  def text_a_message(message)
    puts message
  end

  public
  def tell_friend(where)
    text_a_message("I just applied to #{where}")
  end
end

#running the code
Worker1 = Worker.new("Steve", "Support")
Worker2 = Worker.new("Alan", "PA")
puts Worker.latest

Can anybody see why?