inconsistent update behavior

[muradm]

This works:

client = ...
instance = client.load(Instance, 123)
instance.tags = ['new-tags']
instance.save()

This does nothing:

client = ...
instance = Instance(client, 123) # from documentation it is not clear that this will make call at all
instance.tags = ['new-tags']
instance.save()

However this does work:

client = ...
volume = Volume(client, 1234)
volume.resize(25)

Same behavior for all objects. Is it intended?

Also could you confirm that first snippet will cause 2 remote API calls while second will cause 3 and how many call at what method calls will cause third snippet?