More Ruby practice from Codeacademy working on using private methods

Account.rb

class Account

  attr_reader :name
  attr_reader :balance

  def initialize(name, balance = 100) 
    @name = name 
    @balance = balance 
  
  end 
  
  def display_balance(pin_number) 
  
    if pin_number == pin
      puts "Balance: #{@balance}"
    else
     puts 
       pin_error 
    end 
  end 
  
  def withdraw(pin_number, amount) 
  
    if pin_number == pin 
      @balance -= amount
      puts "Withdrew #{amount}. New balance: $#{@balace}."
    else
      puts pin_error
    end
  
  end 
  
  private 
  
  def pin 
    @pin = 1234
  end 
  
  def pin_error
    return "Access denied: incorrect PIN."
  end 


end