Need help-Balance not defined for checking error in ruby exercise

class Accounts

attr_accessor :checking, :balance, :checking_bal

def initialize(checking, savings)
@checking = checking
@savings = savings
end

def debit(account, amount)
account.balance += amount
end

def balance
if account == “checking”
return @checking
else if account ==“savings”
return @savings
end
end
end
end

ac1 = Accounts.new(500, 1000)

ac1.debit(“checking”, 100)

puts ac1.checking