extract_class_pt_3.rb

def items
  [ShopItem.new(20, "Paper"),
    ShopItem.new(50, "Ball"),
    ShopItem.new(40, "Book"),
    ShopItem.new(4, "Chips")]
end 


def find_item(item_name)
  items.select do | item | 
    item.name == item_name 
  end.first
end 

item = "Ball"
searched_item = find_item(item)
unless searched_item.nil?
  money = perform_transaction(money, searched_item) 
else 
  puts "We don't sell that item"    
end