Convert dynamic python object to json [duplicate]

Possible Duplicate:
Python serializable objects json

I need to know how to convert a dynamic python object into JSON. The object must be able to have multiple levels object child objects. For example:

class C(): pass
class D(): pass

c = C()
c.dynProperty1 = "something"
c.dynProperty2 = { 1, 3, 5, 7, 9 }
c.d = D()
c.d.dynProperty3 = "d.something"

# ... convert c to json ...

Using python 2.6 the following code:

import json

class C(): pass
class D(): pass

c = C()
c.what = "now?"
c.now = "what?"
c.d = D()
c.d.what = "d.what"

json.dumps(c.__dict__)

yields the following error:

TypeError: <__main__.D instance at 0x99237ec> is not JSON serializable

I don't know what types of subobjects a user might put into c. Is there a solution that is smart enough to detect if an attribute is an object and parse it's __dict__ automatically?

UPDATED to include subobjects on c.

Specify the default= parameter ^(doc):

json.dumps(c, default=lambda o: o.__dict__)

json.dumps(c.__dict__)

That will give you a generic JSON object, if that's what you're going for.