how to traverse SDK2MutationResult return by upsert_multi

ON 6.5.0-4960 

1. enable development preview 
2. create 2 collection in a 2 node cluster 
3. load 150 documents to 2 collections using upsert multi 
4. upsert multi returns SDK2MutationObject for each key 
5.  How to iterate through the object and find if the set is success or failure?
6. I couldn't find any documentation on this object {'test_docs-111': <couchbase.result.SDK2MutationResult object at 0x1120d0e50>, 'test_docs-112': <couchbase.result.SDK2MutationResult object at 0x1120d0e90>, 'test_docs-113': <couchbase.result.SDK2MutationResult object at 0x1120d0ed0>, 'test_docs-114': <couchbase.result.SDK2MutationResult object at 0x1120d0f10>, 'test_docs-115': <couchbase.result.SDK2MutationResult object at 0x1120d0f50>, 'test_docs-116': <couchbase.result.SDK2MutationResult object at 0x1120d0f90>, 'test_docs-117': <couchbase.result.SDK2MutationResult object at 0x1120d0fd0>, 'test_docs-118': <couchbase.result.SDK2MutationResult object at 0x1120e6050>, 'test_docs-119': <couchbase.result.SDK2MutationResult object at 0x1120e6090>, 'test_docs-120': <couchbase.result.SDK2MutationResult object at 0x1120e60d0>, 'test_docs-121': <couchbase.result.SDK2MutationResult object at 0x1120e6110>, 'test_docs-122': <couchbase.result.SDK2MutationResult object at 0x1120e6150>, 'test_docs-123': <couchbase.result.SDK2MutationResult object at 0x1120e6190>, 'test_docs-124': <couchbase.result.SDK2MutationResult object at 0x1120e61d0>

1. We are blocked in our testing as we are not able to translate SDK2MutationResult object