opportunity for a anonymous block?

gistfile1.rb

def under_minimum_order_size?(min = minimum_order_size, total = total_quantity_in_instance)    
    errors.add(:under_min, "Total quantity must be over #{min}") if total < min
  end

  def total_quantity_in_instance(total = 0)
    self.custom_sizes.each do |custom_size|
      total += custom_size.quantity.to_i
    end
    total
  end

  def minimum_order_size(min = 12)
    min = 25 if self.custom_product.parent_product_type_name == "swim cap"
    min
  end