def empty_values(obj)
      values = case obj
               when Hash         then obj
               when StripeObject then obj.instance_variable_get(:@values)
               else
                 raise ArgumentError, "#empty_values got unexpected object type: #{obj.class.name}"
               end

      values.each_with_object({}) do |(k, _), update|
        update[k] = ""
      end
    end
def empty_values(obj)
      values = case obj
               when Hash         then obj
               when StripeObject then obj.instance_variable_get(:@values)
               else
                 raise ArgumentError, "#empty_values got unexpected object type: #{obj.class.name}"
               end

      values.each_with_object({}) do |(k, _), update|
        update[k] = ""
      end
    end
Returns a hash of empty values for all the values that are in the given
 StripeObject.