use _dump and self._load instead of marshal_*

lib/stripe/stripe_object.rb

@@ -102,17 +102,18 @@ module Stripe
       @values.each(&blk)
     end
 
-    def marshal_dump
-      @values
+    def _dump(level)
+      [Marshal.dump(@values), @api_key].join("--::--")
     end
 
-    def marshal_load(values)
-      @values = values
+    def self._load(args)
+      hash = args.split("--::--")
+      construct_from(Marshal.load(hash[0]), hash[1])
     end
 
     if RUBY_VERSION < '1.9.2'
       def respond_to?(symbol)
-        @values && @values.has_key?(symbol) || super
+        @values.has_key?(symbol) || super
       end
     end
 

test/stripe/stripe_object_test.rb

@@ -10,10 +10,11 @@ module Stripe
     end
 
     should "marshal a stripe object correctly" do
-      obj = Stripe::StripeObject.construct_from({ :id => 1, :name => 'Stripe' })
+      obj = Stripe::StripeObject.construct_from({ :id => 1, :name => 'Stripe' }, 'apikey')
       m = Marshal.load(Marshal.dump(obj))
       assert_equal m.id, 1
       assert_equal m.name, 'Stripe'
+      assert_equal m.api_key, 'apikey'
     end
   end
 end