Cannot get a method instance to function; How to use an Each Do method in ruby?

I have an specific method that I would like to call so that I can see the balances for 'accounts'. The method is;

 def report_balances(accounts)
   accounts.each do |account|
    puts account.balance
   end
 end

I am not sure but I have either built the above method incorrectly or I am calling it incorrectly or maybe I have placed the method correctly in my code.

class BankAccount
  attr_reader :balance

  def initialize(balance)
    @balance = balance
  end

  def deposit(amount)
    @balance += amount if amount >= 0
  end

  def withdraw(amount)
    @balance -= amount if @balance >= amount
  end
end

class SavingsAccount < BankAccount
  attr_reader :number_of_withdrawals
  APY = 0.0017

  def initialize(balance)
    super(balance) # calls the parent method
    @number_of_withdrawals = 0 # then continues here
  end

  def end_of_month_closeout
    if @balance > 0
      interest_gained = (@balance * APY) / 12
      @balance += interest_gained
    end
    @number_of_withdrawals = 0
  end

 def report_balances(accounts)
  accounts.each do |account|
    puts account.balance
   end
 end

end

I would like to see the balances of the objects:

my_account = SavingsAccount.new(100)

and

account = BankAccount.new(2500)

by calling

'report_balances(accounts)'

How would this be accomplished?