In https://github.com/google/oauth2client/blob/0aad0a09f50312e0fcc3a1234f0e7fb525010bfd/oauth2client/gce.py#L86, the code uses d = json.loads(content) to load content as JSON. The code is broken in Python 3 because content is binary, while json.loads expects string.