Will OpenCV 3.2+ FileStorage save the SimpleBlobDetector_create object in XML or YML?
I have lately had some troubles when using FileStorage with XML or YAML (It appears to be some kind of bug in the OpenCV sourcecode). I would recommend you to try it with JSON. In oder to do so, just change the name of the file to XXXX.json. If you are saving self-constructed structures as well, just construct the structure as if it was a YAML and change the filename to .json.
I hope this helps you further. 
Regards, David
I am fairly new to OpenCV 3+ in Python. It looks to me that FileStorage under Python does not support, for example, a writeObj() method. Is it possible to save the SimpleBlobDetector_create to an XML or YAML file using OpenCV 3+ in Python?  Another way to put it is this: using Python OpenCV, can I save XML/YAML data that is not a numpy array or a scalar (e.g. an object)?