Serializing class instance to JSON

I am trying to create a JSON string representation of a class instance and having difficulty. Let's say the class is built like this:

class testclass:
    value1 = "a"
    value2 = "b"

A call to the json.dumps is made like this:

t = testclass()
json.dumps(t)

It is failing and telling me that the testclass is not JSON serializable.

TypeError: <__main__.testclass object at 0x000000000227A400> is not JSON serializable

I have also tried using the pickle module :

t = testclass()
print(pickle.dumps(t, pickle.HIGHEST_PROTOCOL))

And it gives class instance information but not a serialized content of the class instance.

b'\x80\x03c__main__\ntestclass\nq\x00)\x81q\x01}q\x02b.'

What am I doing wrong?